Use HAVE_PATA_PLATFORM for ARCH_RPC

Cc: Linux ARM Kernel <linux-arm-kernel@lists.arm.linux.org.uk>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>