ARM: 5812/1: SA1100: h3100/h3600: separate machine-specific LCD helpers

h3100 and h3600 have different sets of LCD-controlling gpios,
which mapped to the same "abstracted" EGPIO.
As we plan to get rid of those abstracted egpios completely, we
need to separate these helper functions.

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