HID: i2c-hid: Disable runtime PM on Synaptics touchpad

We have a new Dell laptop which has the synaptics I2C touchpad
(06cb:7e7e) on it. After booting up the Linux, the touchpad doesn't
work, there is no interrupt when touching the touchpad, after
disable the runtime PM, everything works well.

I also tried the quirk of I2C_HID_QUIRK_DELAY_AFTER_SLEEP, it is
better after applied this quirk, there are interrupts but data it
reports is invalid.

Signed-off-by: Hui Wang <hui.wang@canonical.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>