s390/bitops: Use correct constraint for arch_test_bit() inline assembly

Use the "Q" instead of "R" constraint to correctly reflect the instruction
format of the tm instruction: the first operand is a memory reference
without index register and short displacement. The "R" constraint indicates
a memory reference with index register instead.

This may lead to compile errors like:

  arch/s390/include/asm/bitops.h: Assembler messages:
  arch/s390/include/asm/bitops.h:60: Error: operand 1: syntax error; missing ')' after base register
  arch/s390/include/asm/bitops.h:60: Error: operand 2: syntax error; ')' not allowed here
  arch/s390/include/asm/bitops.h:60: Error: junk at end of line: `,4'

Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/r/20250122-s390-fix-std-for-gcc-15-v1-1-8b00cadee083@kernel.org


Fixes: b2bc1b1a ("s390/bitops: Provide optimized arch_test_bit()")
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>