[media] exynos4-is: Fix off-by-one valid range checking for is->config_index

Current code uses is->config_index as array subscript, thus the valid value
range is 0 ... ARRAY_SIZE(cmd) - 1.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/platform/exynos4-is/fimc-is-regs.c

@@ -174,7 +174,7 @@ int fimc_is_hw_change_mode(struct fimc_is *is)
 		HIC_CAPTURE_STILL, HIC_CAPTURE_VIDEO,
 	};
 
-	if (WARN_ON(is->config_index > ARRAY_SIZE(cmd)))
+	if (WARN_ON(is->config_index >= ARRAY_SIZE(cmd)))
 		return -EINVAL;
 
 	mcuctl_write(cmd[is->config_index], is, MCUCTL_REG_ISSR(0));