When I2C client is instantiated with I2C_CLIENT_WAKE flag (either via
"wakeup-source" device property, or via board info flag), it will mark the
main IRQ line as wakeup IRQ, which will ensure that it will be enabled for
wakeup when system transitions to suspend state. Since our suspend/resume
handlers were only managing IRQ wakeup state, they are no longer needed,
and can be removed.

Tested-by: Adam Ford <aford173@gmail.com> #imx6q-logicpd
Tested-by: Sven Van Asbroeck <TheSven73@gmail.com> # ILI2118A variant
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>