[X86][KCFI] Add support for memory operand unfolding

When the Linux kernel is compiled without -mretpoline, KCFI fails
ungracefully because it doesn't handle indirect calls with a memory
target operand. Since the KCFI check will need to load the target
address into a register for validating the type hash anyway, simply
unfold memory operands in indirect calls that need a KCFI check.

Fixes #59017