[PATCH] ppc64: Add missing exports

This patch adds a couple of missing symbol exports.  flush_dcache_page is
used by the AGP driver and rtc_lock by the RTC driver.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>