input: synaptics_i2c_rmi4: Switch suspend control to debugfs

Move control over suspend/resume control to debugfs from
sysfs.

This patch is propagated from msm-3.4 kernel.
(commit: 986863d096dfaee949fb99dc1cbd26a35c5c2f58
input: synaptics_i2c_rmi4: Switch suspend control to debugfs)

Change-Id: I6f0e25779a8d0a47b53f3c4b41a73a731ddc0018
Signed-off-by: Amy Maloche <amaloche@codeaurora.org>