gpio: pca953x: enfore type for i2c_smbus_write_word_data()

The commit 9b8e3ec3 ("gpio: pca953x: Use correct u16 value for register
word write") fixed regression in pca953x_write_regs(). At the same time the
solution introduced a sparse warning:

drivers/gpio/gpio-pca953x.c:168:39: warning: incorrect type in argument 3 (different base types)
drivers/gpio/gpio-pca953x.c:168:39:    expected unsigned short [unsigned] [usertype] value
drivers/gpio/gpio-pca953x.c:168:39:    got restricted __le16 [usertype] <noident>

Fix the code by enforcing the type of i2c_smbus_write_word_data() parameter.

Cc: Yong Li <sdliyong@gmail.com>
Cc: Phil Reid <preid@electromag.com.au>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-pca953x.c

@@ -163,10 +163,13 @@ static int pca953x_write_regs(struct pca953x_chip *chip, int reg, u8 *val)
 					NBANK(chip), val);
 	} else {
 		switch (chip->chip_type) {
-		case PCA953X_TYPE:
-			ret = i2c_smbus_write_word_data(chip->client,
-			    reg << 1, cpu_to_le16(get_unaligned((u16 *)val)));
+		case PCA953X_TYPE: {
+			__le16 word = cpu_to_le16(get_unaligned((u16 *)val));
+
+			ret = i2c_smbus_write_word_data(chip->client, reg << 1,
+							(__force u16)word);
 			break;
+		}
 		case PCA957X_TYPE:
 			ret = i2c_smbus_write_byte_data(chip->client, reg << 1,
 							val[0]);