powerpc: Use rwsem.h from generic location

As of commit dd472da38, rwsem.h was moved into asm-generic.
This patch removes the arch file and points the build at
its new location.

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2 files changed