ARM: dts: STi: Fix aliases property name for STi boards

Update serial aliases from "ttyASN" to more common "serialN".

Since dtc v1.4.6-9-gaadd0b65c987, aliases property name must
be lowercase only. This allows to fix following dtc warnings:

arch/arm/boot/dts/stih418-b2199.dtb: Warning (alias_paths): /aliases: aliases property name must include only lowercase and '-'
arch/arm/boot/dts/stih407-b2120.dtb: Warning (alias_paths): /aliases: aliases property name must include only lowercase and '-'
arch/arm/boot/dts/stih410-b2260.dtb: Warning (alias_paths): /aliases: aliases property name must include only lowercase and '-'
arch/arm/boot/dts/stih410-b2120.dtb: Warning (alias_paths): /aliases: aliases property name must include only lowercase and '-'

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/arm/boot/dts/stih407-b2120.dts

@@ -24,7 +24,7 @@
 	};
 
 	aliases {
-		ttyAS0 = &sbc_serial0;
+		serial0 = &sbc_serial0;
 		ethernet0 = &ethernet0;
 	};
 

arch/arm/boot/dts/stih410-b2120.dts

@@ -24,7 +24,7 @@
 	};
 
 	aliases {
-		ttyAS0 = &sbc_serial0;
+		serial0 = &sbc_serial0;
 		ethernet0 = &ethernet0;
 	};
 

arch/arm/boot/dts/stih410-b2260.dts

@@ -25,7 +25,7 @@
 	};
 
 	aliases {
-		ttyAS1 = &uart1;
+		serial1 = &uart1;
 		ethernet0 = &ethernet0;
 	};
 

arch/arm/boot/dts/stih418-b2199.dts

@@ -24,7 +24,7 @@
 	};
 
 	aliases {
-		ttyAS0 = &sbc_serial0;
+		serial0 = &sbc_serial0;
 		ethernet0 = &ethernet0;
 	};