ARM: dts: ti: omap: Fix noisy serial with overrun-throttle-ms for mapphone

On mapphone devices we may get lots of noise on the micro-USB port in debug
uart mode until the phy-cpcap-usb driver probes. Let's limit the noise by
using overrun-throttle-ms.

Note that there is also a related separate issue where the charger cable
connected may cause random sysrq requests until phy-cpcap-usb probes that
still remains.

Cc: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Cc: Carl Philipp Klemm <philipp@uvos.xyz>
Cc: Merlijn Wajer <merlijn@wizzup.org>
Cc: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/ti/omap/motorola-mapphone-common.dtsi

@@ -640,6 +640,7 @@ &uart1 {
 &uart3 {
 	interrupts-extended = <&wakeupgen GIC_SPI 74 IRQ_TYPE_LEVEL_HIGH
 			       &omap4_pmx_core 0x17c>;
+	overrun-throttle-ms = <500>;
 };
 
 &uart4 {