ARM: SAMSUNG: Gracefully exit on suspend failure

As per the Exynos5250 User Manual:
When there are pending interrupt events, WFI/WFE instruction are
ignored. To cancel the power-down sequence follow these steps:
1) Disable system power-down using CENTRAL_SEQ_CONFIGURATION register
2) Clear WAKEUP_STAT register
3) Enable interrupt service routine for CPU

Code for early wakeup for exynos already exists. Remove the panic
on suspend failure, clear the wakeup state register and return 1
from cpu_suspend to indicate a failed suspend (to a user daemon).

Older Samsung SoCs have similar panics and I have removed them all.
Haven't touched the S3C2410 sleep code.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>