pinctrl: sprd: Simplify bool comparison

Fix the following coccicheck warning:
./drivers/pinctrl/sprd/pinctrl-sprd.c:690:8-23: WARNING: Comparison to
bool
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: YANG LI <abaci-bugfix@linux.alibaba.com>
Reviewed-by: Baolin Wang <baolin.wang7@gmail.com>
Link: https://lore.kernel.org/r/1610440080-68600-1-git-send-email-abaci-bugfix@linux.alibaba.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/sprd/pinctrl-sprd.c

@@ -687,7 +687,7 @@ static int sprd_pinconf_set(struct pinctrl_dev *pctldev, unsigned int pin_id,
 				shift = INPUT_SCHMITT_SHIFT;
 				break;
 			case PIN_CONFIG_BIAS_PULL_UP:
-				if (is_sleep_config == true) {
+				if (is_sleep_config) {
 					val |= SLEEP_PULL_UP;
 					mask = SLEEP_PULL_UP_MASK;
 					shift = SLEEP_PULL_UP_SHIFT;