x86: Update register operand check for AddrPrefixOpReg

x86: Update register operand check for AddrPrefixOpReg

When the address size prefix applies to both the memory and the register
operand, we need to extract the address size prefix from the register
operand if the memory operand has no real registers, like symbol, DISP
or symbol(%rip).

NB: GCC always generates symbol(%rip) for RIP-relative addressing for
both x32 and x86-64.

Move the .code16 tests in movdir.s to movdir-16bit to show the correct
output from objdump.

	PR gas/26685
	* config/tc-i386.c (process_suffix): Also check the register
	operand for the address size prefix if the memory operand has
	no real registers.
	* testsuite/gas/i386/enqcmd-16bit.d: New file.
	* testsuite/gas/i386/enqcmd-16bit.s: Likewise.
	* testsuite/gas/i386/movdir-16bit.d: Likewise.
	* testsuite/gas/i386/movdir-16bit.s: Likewise.
	* testsuite/gas/i386/enqcmd.s: Add tests with symbol and DISP.
	* testsuite/gas/i386/x86-64-enqcmd.s: Likewise.
	* testsuite/gas/i386/x86-64-movdir.s: Likewise.
	* testsuite/gas/i386/movdir.s: Add tests with symbol and DISP.
	Remove the .code16 test.
	* testsuite/gas/i386/i386.exp: Run movdir-16bit and enqcmd-16bit.
	* testsuite/gas/i386/x86-64-enqcmd-intel.d: Updated.
	* testsuite/gas/i386/x86-64-enqcmd.d: Likewise.
	* testsuite/gas/i386/x86-64-movdir-intel.d: Likewise.
	* testsuite/gas/i386/x86-64-movdir.d: Likewise.
	* testsuite/gas/i386/enqcmd-intel.d: Likewise.
	* testsuite/gas/i386/enqcmd.d: Likewise.
	* testsuite/gas/i386/movdir-intel.d: Likewise.
	* testsuite/gas/i386/movdir.d: Likewise.
	* testsuite/gas/i386/x86-64-enqcmd-intel.d: Likewise.
	* testsuite/gas/i386/x86-64-enqcmd.d: Likewise.
	* testsuite/gas/i386/x86-64-movdir-intel.d: Likewise.
	* testsuite/gas/i386/x86-64-movdir.d: Likewise.