marvell: uart: a3720: Update delay code to be compatible with 1200 MHz CPU

Console initialization function needs to wait at least minimal specified
time. The fastest Armada 3720 CPU is 1200 MHz so increase loop delay to
wait at least for 100 us on 1200 MHz variant too. The slowest Armada 3720
CPU is 600 MHz and in this case delay loop would take just 2 times more,
which is not a problem.
Signed-off-by: Pali Rohár <pali@kernel.org>
Change-Id: I1f0b4aabd0e08b7696feec631419f7f7c7ec17d2

drivers/marvell/uart/a3700_console.S

@@ -72,7 +72,7 @@ func console_a3700_core_init
 	b.ne	4f
 
 	/* Delay */
-	mov	w2, #30000	/* 30000 cycles of below 3 instructions on 600 MHz CPU ~~ 100 us */
+	mov	w2, #60000	/* 60000 cycles of below 3 instructions on 1200 MHz CPU ~~ 100 us */
 3:
 	sub     w2, w2, #1
 	cmp	w2, #0