ARM: integrator: localize the impd1.h header

As we move toward multiplatform support for the Integrator family
we need to localize all <mach/*> headers. This moves the impd1.h
header down to the machine folder, copying the the three defines
only used by the clock driver down into the clock driver.

Cc: Will Deacon <will.deacon@arm.com>
Cc: Jonathan Austin <jonathan.austin@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>