x86inc: Add template defines for EVEX broadcasts

Broadcasting a memory operand is a binary flag, you either broadcast
or you don't, and there's only a single possible element size for
any given instruction.

The instruction syntax however requires the broadcast semanticts
to be explicitly defined, which is an issue when using macros to
template code for multiple register widths.

Add some helper defines to alleviate the issue.

common/x86/x86inc.asm

@@ -1041,6 +1041,9 @@ BRANCH_INSTR jz, je, jnz, jne, jl, jle, jnl, jnle, jg, jge, jng, jnge, ja, jae,
     %if WIN64
         AVX512_MM_PERMUTATION 6 ; Swap callee-saved registers with volatile registers
     %endif
+    %xdefine bcstw 1to8
+    %xdefine bcstd 1to4
+    %xdefine bcstq 1to2
 %endmacro
 
 %macro INIT_YMM 0-1+
@@ -1054,6 +1057,9 @@ BRANCH_INSTR jz, je, jnz, jne, jl, jle, jnl, jnle, jg, jge, jng, jnge, ja, jae,
     INIT_CPUFLAGS %1
     DEFINE_MMREGS ymm
     AVX512_MM_PERMUTATION
+    %xdefine bcstw 1to16
+    %xdefine bcstd 1to8
+    %xdefine bcstq 1to4
 %endmacro
 
 %macro INIT_ZMM 0-1+
@@ -1067,6 +1073,9 @@ BRANCH_INSTR jz, je, jnz, jne, jl, jle, jnl, jnle, jg, jge, jng, jnge, ja, jae,
     INIT_CPUFLAGS %1
     DEFINE_MMREGS zmm
     AVX512_MM_PERMUTATION
+    %xdefine bcstw 1to32
+    %xdefine bcstd 1to16
+    %xdefine bcstq 1to8
 %endmacro
 
 INIT_XMM