Fix a regression in the 32-bit port from the 64-bit port landing.

We now compile CodeGen/X86/lea-2.ll into:

_test:
        movl 4(%esp), %eax
        movl 8(%esp), %ecx
        leal -5(%ecx,%eax,4), %eax
        ret

instead of:

_test:
        movl 4(%esp), %eax
        leal (,%eax,4), %eax
        addl 8(%esp), %eax
        addl $4294967291, %eax
        ret

llvm-svn: 30288