board/orangepi/common/genimage.cfg: use quotes around "gpt"

Like we do in all other genimage configuration files.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

board/orangepi/common/genimage.cfg

@@ -7,7 +7,7 @@ image sdcard.img {
 	}
 
 	hdimage {
-		partition-table-type = gpt
+		partition-table-type = "gpt"
 		gpt-location = 1008K # 1MB - 16KB(GPT)
 		gpt-no-backup = true
 	}