x86/insn-eval: Fix function param name in get_eff_addr_sib()

Change "regoff" to "base_offset" in 2 places in the kernel-doc comments to
prevent warnings:

  insn-eval.c:1152: warning: Function parameter or member 'base_offset' not described in 'get_eff_addr_sib'
  insn-eval.c:1152: warning: Excess function parameter 'regoff' description in 'get_eff_addr_sib'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240211062452.16411-1-rdunlap@infradead.org