ARM: 5819/1: SA1100: h3100/h3600: merge h3600.h and h3600_gpio.h into h3xxx.h

Combine both headers into one, rename to h3xxx.h and change all
users accordingly.

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