drivers/misc/apds9802als.c: add runtime PM support

Update the driver for the needed runtime power features.  Remove the old
user controlled power functions.

[akpm@linux-foundation.org: put PM code under CONFIG_PM]
Signed-off-by: Hong Liu <hong.liu@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>