arm: dts: omap: add reg-shift to serial device tree node

With the commit 'c7b9686d5d48 ("ns16550: unify serial_omap")' all
TI platforms are broken with DM/DT boot as ns16550 driver expects
reg-shift from DT which is not populated for TI platforms.
Earlier it worked as it was hard coded to 2 in serial-omap
driver. So adding the reg-shift to serial nodes for dra7, am4372
and am33xx dtsi files. Tested this patch on am437x-sk-evm,
am437x-gp-evm, am335x-boneblack, dra74x-evm and dra72x-evm.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Thomas Chou <thomas@wytron.com.tw>
diff --git a/arch/arm/dts/am33xx.dtsi b/arch/arm/dts/am33xx.dtsi
index 21fcc44..b26e21b 100644
--- a/arch/arm/dts/am33xx.dtsi
+++ b/arch/arm/dts/am33xx.dtsi
@@ -214,6 +214,7 @@
 			ti,hwmods = "uart1";
 			clock-frequency = <48000000>;
 			reg = <0x44e09000 0x2000>;
+			reg-shift = <2>;
 			interrupts = <72>;
 			status = "disabled";
 			dmas = <&edma 26>, <&edma 27>;
@@ -225,6 +226,7 @@
 			ti,hwmods = "uart2";
 			clock-frequency = <48000000>;
 			reg = <0x48022000 0x2000>;
+			reg-shift = <2>;
 			interrupts = <73>;
 			status = "disabled";
 			dmas = <&edma 28>, <&edma 29>;
@@ -236,6 +238,7 @@
 			ti,hwmods = "uart3";
 			clock-frequency = <48000000>;
 			reg = <0x48024000 0x2000>;
+			reg-shift = <2>;
 			interrupts = <74>;
 			status = "disabled";
 			dmas = <&edma 30>, <&edma 31>;
@@ -247,6 +250,7 @@
 			ti,hwmods = "uart4";
 			clock-frequency = <48000000>;
 			reg = <0x481a6000 0x2000>;
+			reg-shift = <2>;
 			interrupts = <44>;
 			status = "disabled";
 		};
@@ -256,6 +260,7 @@
 			ti,hwmods = "uart5";
 			clock-frequency = <48000000>;
 			reg = <0x481a8000 0x2000>;
+			reg-shift = <2>;
 			interrupts = <45>;
 			status = "disabled";
 		};
@@ -265,6 +270,7 @@
 			ti,hwmods = "uart6";
 			clock-frequency = <48000000>;
 			reg = <0x481aa000 0x2000>;
+			reg-shift = <2>;
 			interrupts = <46>;
 			status = "disabled";
 		};