resolve RIP in some x86 fp semantics

[Angs12]

Bug

During lifting some fp x86 instructions to BIL the RIP is not resolved:

bap mc --show-insn=asm --show-bil -- 0f 54 0d 2a 00 00 00     
andps 0x2a(%rip), %xmm1
{
  YMM1 := high:128[YMM1].127:0[YMM1] & mem[RIP + 0x2A, el]:u128
}

Fix

This pr adds the reg# function already in x86-64.lisp that resolves the PC to the bitwise-rrm macro

The reg# function hardcodes the value 8 for the instruction length, but x86 instructions have variable lenght,
so i added a primus lisp primitive that uses provides the instruction length in bytes that is already in Knowledge Base
and substituted the hardcoded values with that primitive

After fix

bap mc --show-insn=asm --show-bil -- 0f 54 0d 2a 00 00 00
andps 0x2a(%rip), %xmm1
{
  YMM1 := high:128[YMM1].127:0[YMM1] & mem[0x31, el]:u128
}