The nmi_on_reset.S functions are used by all ARM platforms. It
makes no sense to repeat the same code for all platforms. Moving
the code from each SOC implementation to arch/arm/core.
The same treatment for the NMI_INIT() macro. Moving it from a per
SOC implementation to the include/arch/arm/cortex_m/nmi.h.
Change-Id: I574d8880a44046cc7b9e1b635e80d6e83657b8c1
Signed-off-by: Dan Kalowsky <daniel.kalowsky@intel.com>