disp: msm: dsi: add const qualifer for device node in get_named_gpio

Add const qualifier for the device_node param in get_named_gpio
function pointer hook to adapt msm-5.15 kernel.

Change-Id: I0129efeff5aeb85b567bf6f2b5d2e45312fab024
Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>

msm/dsi/dsi_parser.c

@@ -897,7 +897,7 @@ end:
 	return -EINVAL;
 }
 
-int dsi_parser_get_named_gpio(struct device_node *np,
+int dsi_parser_get_named_gpio(const struct device_node *np,
 				const char *propname, int index)
 {
 	int gpio = -EINVAL;