SVD viewer doesn't respect big endian setting

[maxgerhardt]

Consider an Nintendo 64 with a big endian MIPS processor. A register is located at 0xa4300004 whose individual bytes (addr + 0, addr + 1, addr + 2, addr + 3) read as

0xa4300004:  0x02    0x02    0x01    0x02
right reading:RSP    RDP     RAC    IO     Version
wrong reading: IO    RAC    RDP    RSP     Version

This is the big endian value 0x02 02 01 02. PlatformiO however doesn't seem to respect this in the SVD file and parses it in little endian, causing a wrong decoding of the fields.

Needed in e.g. https://github.com/maxgerhardt/platform-nintendon64

Endian setting for SVD is e.g. documented at https://arm-software.github.io/CMSIS_5/SVD/html/elem_cpu.html