Minor comment cleanup.

- fw/boot/boot.c (boot_loader): removed GTA01/GTA02-specific comments
- fw/boot/boot.c (boot_loader, main): documented SYSCLK settings

fw/boot/boot.c

@@ -132,28 +132,7 @@ static void delay(void)
 
 static void boot_loader(void)
 {
-	/*
-	 * If we have VBUS, proceed as follows:
-	 * - bring up USB
-	 * - try to contact the PMU (in a loop)
-	 * - possible transitions:
-	 *   - DFU gets selected -> enter DFU mode
-	 *   - PMU responds -> jump to payload
-	 *
-	 * In DFU mode, the following transitions are possible:
-	 * - VBUS drops -> reset
-	 * - USB bus reset -> reset
-	 *
-	 * @@@ this may be too complex - probably don't really need to talk to
-	 * the PMU.
-	 */
-
-	/*
-	 * Note: if we do anything that delays CPU bringup after nRESET goes
-	 * high, we must still stay in the 100ms budget for raising KEEPACT.
-	 */
-
-	OSCICN |= IFCN0 | IFCN1;
+	OSCICN |= IFCN0 | IFCN1;	/* SYSCLK = IOSC/1 (12 MHz) */
 
 #ifdef LOW_SPEED
 
@@ -235,7 +214,7 @@ void main(void)
 	 * - jump directly to the payload
 	 */
 
-	OSCICN |= IFCN0;
+	OSCICN |= IFCN0;	/* SYSCLK = IOSC/4  (3 MHz) */
 
 	uart_init(3);