For consistency with other architectures, warn about including
<asm-xtensa/rwsem.h> directly.
Signed-off-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NChris Zankel <chris@zankel.net>