ARM: pm: move cpu_init() call into core code

As we have core code dealing with CPU suspend/resume, we can
re-initialize the CPUs exception banked registers via that code rather
than having platforms deal with that level of detail.  So, move the
call to cpu_init() out of platform code into core code.

Tested-by: Kevin Hilman <khilman@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>