i386: Fix operand order for @wrss<mode> and @wruss<mode> [PR124366]

These two insns were using the same operand order for both -masm=att
and -masm=intel, which is ok if using the same operand for both, but not
when they are different.

2026-03-05  Jakub Jelinek  <jakub@redhat.com>

	PR target/124366
	* config/i386/i386.md (@wrss<mode>, @wruss<mode>): Swap operand
	order for -masm=intel.

	* gcc.target/i386/cet-pr124366.c: New test.