Staging: fbtft: Fix some typo. pdc8544 --> pcd8544

The driver is related to 'pcd8544'.
However, 2 strings are about pdc8544 (c and d switched)
Fix it.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/20190725183856.17616-1-christophe.jaillet@wanadoo.frSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fbtft/fb_pcd8544.c

@@ -157,10 +157,10 @@ static struct fbtft_display display = {
 	.backlight = 1,
 };
 
-FBTFT_REGISTER_DRIVER(DRVNAME, "philips,pdc8544", &display);
+FBTFT_REGISTER_DRIVER(DRVNAME, "philips,pcd8544", &display);
 
 MODULE_ALIAS("spi:" DRVNAME);
-MODULE_ALIAS("spi:pdc8544");
+MODULE_ALIAS("spi:pcd8544");
 
 MODULE_DESCRIPTION("FB driver for the PCD8544 LCD Controller");
 MODULE_AUTHOR("Noralf Tronnes");