trivial: fix typos in comments s/DGBU/DBGU/

DBGU means Debug Unit, was refered as "DGBU" in some files. Fixed to "DBGU".

Signed-off-by: Samuel R. C. Vale <srcvale@holoscopio.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/arch/arm/mach-at91/board-neocore926.c b/arch/arm/mach-at91/board-neocore926.c
index 9ba7ba2..8c0b71c 100644
--- a/arch/arm/mach-at91/board-neocore926.c
+++ b/arch/arm/mach-at91/board-neocore926.c
@@ -56,7 +56,7 @@
 	/* Initialize processor: 20 MHz crystal */
 	at91sam9263_initialize(20000000);
 
-	/* DGBU on ttyS0. (Rx & Tx only) */
+	/* DBGU on ttyS0. (Rx & Tx only) */
 	at91_register_uart(0, 0, 0);
 
 	/* USART0 on ttyS1. (Rx, Tx, RTS, CTS) */