power: reset: ltc2952: unroll gpio_desc array

The three gpio's used by this driver are stored in an array of pointers.
This doesn't add much besides cleanups in a loop. In fact, it makes most
of the usage sites harder to read. Unroll the loop, and live with the
fact that cleanups become slightly larger.

Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>