ARM: 8181/1: Drop extra return statement

Commit 513510ddba9650fc7da456eefeb0ead7632324f6
(common: dma-mapping: introduce common remapping functions)
managed to end up with an extra return statement from the
original patch. Drop it.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>