Remove dest!=0 restriction from LC

The CHERI ISAv9 encoding with rd/cd=0 conflicted with the CBO
instructions, but this is no longer the case.

Fixes #52

src/insns/wavedrom/loadcap.adoc

@@ -4,7 +4,7 @@
 ....
 {reg: [
   {bits: 7,  name: 'opcode',    attr: ['7', 'MISCMEM=0001111', 'MISCMEM=0001111', 'LOAD=0000011', 'LOAD=0000011'], type: 8},
-  {bits: 5,  name: 'cd', attr: ['5', 'dest!=c0'], type: 2},
+  {bits: 5,  name: 'cd', attr: ['5', 'dest'], type: 2},
   {bits: 3,  name: 'funct3', attr: ['3', 'cap rv64: CLC=100', 'leg rv64: LC=100', 'cap rv32: CLC=011','leg rv32: LC=011'], type: 8},
   {bits: 5,  name: 'rs1/cs1', attr: ['5', 'base'], type: 4},
   {bits: 12, name: 'imm[11:0]', attr: ['12', 'offset[11:0]'], type: 3},