pinctrl: bm1880: add pwm37 to bm1880_pctrl_groups

The 'pwm37' is not added to bm1880_pctrl_groups, which triggers a gcc
build warning:

drivers/pinctrl/pinctrl-bm1880.c:263:27: warning: ‘pwm37_pins’ defined
but not used [-Wunused-const-variable=]
 static const unsigned int pwm37_pins[] = { 110 };

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200428115543.33379-1-yanaijie@huawei.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>