video: fbdev: pxafb: match_string() conversion fixup

"unknown" lcd_types[] entry is needed for proper operation of
the driver, add it back.

Fixes: 6d09dfe70f8f ("video: fbdev: pxafb: Convert to use match_string() helper")
Reported-by: Andy Shevchenko <[e-mail]>
Cc: Arvind Yadav <[e-mail]>
Signed-off-by: Bartlomiej Zolnierkiewicz <[e-mail]>

drivers/video/fbdev/pxafb.c

···
 
 #if defined(CONFIG_OF)
 static const char * const lcd_types[] = {
-	"mono-stn", "mono-dstn", "color-stn", "color-dstn",
+	"unknown", "mono-stn", "mono-dstn", "color-stn", "color-dstn",
 	"color-tft", "smart-panel", NULL
 };