x86: Add limited support for extracting function call arguments
x86: Add limited support for extracting function call arguments

Add support for extracting the first 6 64-bit integer argumements to a
function call in X86ISA::getArgument().

andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin,andrewfu0325/gem5-aladdin