Merge branch 'reset/of-get-optional-exclusive' of git://git.pengutronix.de/pza/linux...

"Add optional variant of of_reset_control_get_exclusive(). If the
requested reset is not specified in the device tree, this function
returns NULL instead of an error."

This dependency is needed for the Generic Timer Module (a.k.a OSTM)
support for RZ/G2L.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>