To decrease the suspend time, move copying the sram function to the sram
initialization phase, instead of every time go to suspend.

In the meanwhile, substitute fncpy() for memcpy().

If there is no sram allocated for PM, the PM is not supported.
Signed-off-by: NWenyou Yang <wenyou.yang@atmel.com>
Acked-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Tested-by: NSylvain Rochet <sylvain.rochet@finsecur.com>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>