ARM: pm: plat-s3c24xx: cleanup s3c_cpu_save

s3c_cpu_save does not need to save any registers with the new
cpu_suspend calling convention.  Remove these redundant instructions.

Tested-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>