uapi: bitops: use UAPI-safe variant of BITS_PER_LONG again

Commit 1e7933a5 ("uapi: Revert "bitops: avoid integer overflow in GENMASK(_ULL)"")
did not take in account that the usage of BITS_PER_LONG in __GENMASK() was
changed to __BITS_PER_LONG for UAPI-safety in
commit 3c7a8e19 ("uapi: introduce uapi-friendly macros for GENMASK").
BITS_PER_LONG can not be used in UAPI headers as it derives from the kernel
configuration and not from the current compiler invocation.
When building compat userspace code or a compat vDSO its value will be
incorrect.

Switch back to __BITS_PER_LONG.

Fixes: 1e7933a5 ("uapi: Revert "bitops: avoid integer overflow in GENMASK(_ULL)"")
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Yury Norov [NVIDIA] <yury.norov@gmail.com>