[ARM] 5426/1: h3600: remove clr_h3600_egpio/set_h3600_egpio helpers

Replace all occurences with assign_h3600_egpio.
Also simplify code a bit by replacing couple of if-else
statements with one-line equivalents.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>