asm-generic: make sparse happy with odd-sized put_unaligned_*()

asm-generic: make sparse happy with odd-sized put_unaligned_*()

[ Upstream commit 1ab33c03145d0f6c345823fc2da935d9a1a9e9fc ]

__put_unaligned_be24() and friends use implicit casts to convert
larger-sized data to bytes, which trips sparse truncation warnings when
the argument is a constant:

    CC [M]  drivers/input/touchscreen/hynitron_cstxxx.o
    CHECK   drivers/input/touchscreen/hynitron_cstxxx.c
  drivers/input/touchscreen/hynitron_cstxxx.c: note: in included file (through arch/x86/include/generated/asm/unaligned.h):
  include/asm-generic/unaligned.h:119:16: warning: cast truncates bits from constant value (aa01a0 becomes a0)
  include/asm-generic/unaligned.h:120:20: warning: cast truncates bits from constant value (aa01 becomes 1)
  include/asm-generic/unaligned.h:119:16: warning: cast truncates bits from constant value (ab00d0 becomes d0)
  include/asm-generic/unaligned.h:120:20: warning: cast truncates bits from constant value (ab00 becomes 0)

To avoid this let's mask off upper bits explicitly, the resulting code
should be exactly the same, but it will keep sparse happy.

Reported-by: kernel test robot <lkp@intel.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Closes: https://lore.kernel.org/oe-kbuild-all/202401070147.gqwVulOn-lkp@intel.com/
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>