x86/percpu: Fix x86_this_cpu_variable_test_bit() asm template

Fix x86_this_cpu_variable_test_bit(), which is implemented with an
incorrect asm template, where argument 2 (count argument) is considered
a percpu variable. However, x86_this_cpu_test_bit() is currently
used exclusively with constant bit number argument, so the called
x86_this_cpu_variable_test_bit() function is never instantiated.

The fix introduces named assembler operands to prevent this kind
of error.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lore.kernel.org/r/20240404094218.448963-1-ubizjak@gmail.com