Fix below build warning

   WARNING: modpost: missing MODULE_LICENSE() in
   drivers/pinctrl/pinctrl-equilibrium.o

Introduced by commit

   1948d5c5 ("pinctrl: Add pinmux & GPIO controller driver for a new SoC")

by adding missing MODULE_LICENSE.
Signed-off-by: NRahul Tanwar <rahul.tanwar@linux.intel.com>
Link: https://lore.kernel.org/r/20191128080832.13529-2-rahul.tanwar@linux.intel.comSigned-off-by: NLinus Walleij <linus.walleij@linaro.org>