gpio: wcd934x: Fix shift-out-of-bounds error

bit-mask for pins 0 to 4 is BIT(0) to BIT(4) however we ended up with BIT(n - 1)
which is not right, and this was caught by below usban check

UBSAN: shift-out-of-bounds in drivers/gpio/gpio-wcd934x.c:34:14

Fixes: 59c32468 ("gpio: wcd934x: Add support to wcd934x gpio controller")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

drivers/gpio/gpio-wcd934x.c

@@ -7,7 +7,7 @@
 #include <linux/slab.h>
 #include <linux/of_device.h>
 
-#define WCD_PIN_MASK(p) BIT(p - 1)
+#define WCD_PIN_MASK(p) BIT(p)
 #define WCD_REG_DIR_CTL_OFFSET 0x42
 #define WCD_REG_VAL_CTL_OFFSET 0x43
 #define WCD934X_NPINS		5