Input: omap4-keypad - fix pm_runtime_get_sync() error checking

If the device is already in a runtime PM enabled state
pm_runtime_get_sync() will return 1, so a test for negative
value should be used to check for errors.

Fixes: f77621cc640a ("Input: omap-keypad - dynamically handle register offsets")
Signed-off-by: Miaoqian Lin <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/keyboard/omap4-keypad.c

···
 	 * revision register.
 	 */
 	error = pm_runtime_get_sync(dev);
-	if (error) {
+	if (error < 0) {
 		dev_err(dev, "pm_runtime_get_sync() failed\n");
 		pm_runtime_put_noidle(dev);
 		return error;