ARM: UniPhier: update the vendor name of UniPhier in Kconfig

The business for UniPhier Soc family has been transferred from
Panasonic Corporation to Socionext Inc.

Update the SoC select menu in Kconfig.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index b62842f..2985e6e 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -786,7 +786,7 @@
 	select CPU_SA1100
 
 config ARCH_UNIPHIER
-	bool "Panasonic UniPhier platform"
+	bool "Socionext UniPhier SoCs"
 	select CPU_V7
 	select SUPPORT_SPL
 	select SPL
@@ -794,6 +794,9 @@
 	select DM
 	select DM_SERIAL
 	select DM_I2C
+	help
+	  Support for UniPhier SoC family developed by Socionext Inc.
+	  (formerly, System LSI Business Division of Panasonic Corporation)
 
 config TARGET_STM32F429_DISCOVERY
 	bool "Support STM32F429 Discovery"