arm: fix comment header and macro name

Commit da660b4a ("arm: Move sp810.h to include/linux/amba/")
moved the file to the current location but forgot to remove the pointer
to its previous location. Clean it up. While at it also change the header
file protection macros appropriately.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>