[PATCH] m32r: revise __raw_read_trylock()

Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>