ARM: ep93xx: keypad: stop using mach/platform.h

We can communicate the clock rate using platform data rather than setting
a flag to use a particular value in the driver, which is cleaner and
avoids the dependency.

No platform in the kernel currently defines the ep93xx keypad device
structure, so this is a rather pointless excercise.  Any out of tree
users are probably dead now, but if not, they have to change their
platform code to match the new platform_data structure.

Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Olof Johansson <olof@lixom.net>