staging: fbtft: Replace custom ->reset() with generic one

The custom ->reset() repeats the generic one, replace it.

Note, in newer kernels the context of the function is a sleeping one,
it's fine to switch over to the sleeping functions. Keeping the reset
line asserted longer than 20 microseconds is also okay, it's an idling
state of the hardware.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210503172114.27891-5-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fbtft/fb_agm1264k-fl.c

@@ -77,19 +77,6 @@ static int init_display(struct fbtft_par *par)
 	return 0;
 }
 
-static void reset(struct fbtft_par *par)
-{
-	if (!par->gpio.reset)
-		return;
-
-	dev_dbg(par->info->device, "%s()\n", __func__);
-
-	gpiod_set_value(par->gpio.reset, 1);
-	udelay(20);
-	gpiod_set_value(par->gpio.reset, 0);
-	mdelay(120);
-}
-
 /* Check if all necessary GPIOS defined */
 static int verify_gpios(struct fbtft_par *par)
 {
@@ -439,7 +426,6 @@ static struct fbtft_display display = {
 		.set_addr_win = set_addr_win,
 		.verify_gpios = verify_gpios,
 		.request_gpios_match = request_gpios_match,
-		.reset = reset,
 		.write = write,
 		.write_register = write_reg8_bus8,
 		.write_vmem = write_vmem,