color_space_helper: Allow 8- and 10-bit fmts for the sRGB color space

Most texture formats should be presentable on the default sRGB color
space, in particular 10-bit formats for higher bit depth and detail than
the typical 8-bit.

A couple notes:
- This currently only affects `VK_KHR_display` as there is a
  `needsWorkaround` case in `PhysicalDevice::GetSurfaceFormats()` that
  returns exclusively RGBA8 and BGRA8 in the windowed/compositor case;
- Before this patch, `A2B10G10R10` wasn't in the list returned by
  `vkGetPhysicalDeviceSurfaceFormatsKHR()` but worked anyway on
  `VK_KHR_display` _without_ validation errors;
- Using the `A2B10G10R10` format inside a 10-bit compositor works
  anyway, albeit with validation layer errors;
- RADV also allows 10-bit sRGB swapchains, but only in a compositor, not
  in `VK_KHR_display`;
- Windows also does not report support for this 10-bit sRGB format
  combination, but it works anyway (also with validation layer errors);
- This was previously `Fmt_All` already before commit 02e867e ("Update
  xgl from commit 2aeb0b25") but it is assumed that sub-commit "Fix
  ColorspaceHelper's lookup table so it only reports formats that are
  legal" changed this behaviour. At least 10-bit sRGB should be retained?

(When saying "it works", I mean that it works as intended, i.e.
any 8-bit banding previously observable is gone when using a 10-bit
swapchain)

icd/api/color_space_helper.cpp

@@ -51,7 +51,7 @@ struct LookupDefines
 
 const LookupDefines colorspaceLookup[] =
 {
-    { Pal::ScreenColorSpace::CsSrgb,         VK_COLOR_SPACE_SRGB_NONLINEAR_KHR,       FmtSupport::Fmt_8bpc         },
+    { Pal::ScreenColorSpace::CsSrgb,         VK_COLOR_SPACE_SRGB_NONLINEAR_KHR,       FmtSupport::Fmt_KnownSRGB    },
     { Pal::ScreenColorSpace::CsBt709,        VK_COLOR_SPACE_BT709_NONLINEAR_EXT,      FmtSupport::Fmt_All          },
     { Pal::ScreenColorSpace::TfHlg,          VK_COLOR_SPACE_HDR10_HLG_EXT,            FmtSupport::Fmt_KnownHDR     },
     { Pal::ScreenColorSpace::TfPq2084,       VK_COLOR_SPACE_HDR10_ST2084_EXT,         FmtSupport::Fmt_10bpc        },

icd/api/include/color_space_helper.h

@@ -62,10 +62,11 @@ class ColorSpaceHelper
         Fmt_16bpc_sfloat = 0x0400,
         Fmt_32bpc        = 0x0800,
 
-        Fmt_8bpc     = Fmt_8bpc_srgb   | Fmt_8bpc_unorm,
-        Fmt_16bpc    = Fmt_16bpc_unorm | Fmt_16bpc_sfloat,
-        Fmt_KnownHDR = Fmt_10bpc | Fmt_11bpc | Fmt_12bpc | Fmt_16bpc,
-        Fmt_All      = Fmt_4bpc  | Fmt_5bpc  | Fmt_6bpc  | Fmt_8bpc  | Fmt_KnownHDR | Fmt_32bpc,
+        Fmt_8bpc      = Fmt_8bpc_srgb   | Fmt_8bpc_unorm,
+        Fmt_16bpc     = Fmt_16bpc_unorm | Fmt_16bpc_sfloat,
+        Fmt_KnownHDR  = Fmt_10bpc | Fmt_11bpc | Fmt_12bpc | Fmt_16bpc,
+        Fmt_KnownSRGB = Fmt_8bpc | Fmt_10bpc,
+        Fmt_All       = Fmt_4bpc  | Fmt_5bpc  | Fmt_6bpc  | Fmt_8bpc  | Fmt_KnownHDR | Fmt_32bpc,
 
         Fmt_FreeSync2 = Fmt_10bpc | Fmt_16bpc,
     };