ARM: remove redudant information from Kconfig files

- "string" type for SYS_* is defined in arch/Kconfig
 - SYS_CPU "armv7" has been replaced with "select CPU_V7"
 - SYS_SOC "tegra124" is already defined in tegra124/Kconfig

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Bo Shen <voice.shen@atmel.com>

board/atmel/sama5d4_xplained/Kconfig

 if TARGET_SAMA5D4_XPLAINED
 
-config SYS_CPU
-	default "armv7"
-
 config SYS_BOARD
 	default "sama5d4_xplained"
 

board/atmel/sama5d4ek/Kconfig

 if TARGET_SAMA5D4EK
 
-config SYS_CPU
-	default "armv7"
-
 config SYS_BOARD
 	default "sama5d4ek"
 

board/nvidia/nyan-big/Kconfig

 if TARGET_NYAN_BIG
 
-config SYS_CPU
-	string
-	default "arm720t" if SPL_BUILD
-	default "armv7" if !SPL_BUILD
-
 config SYS_BOARD
-	string
 	default "nyan-big"
 
 config SYS_VENDOR
-	string
 	default "nvidia"
 
-config SYS_SOC
-	string
-	default "tegra124"
-
 config SYS_CONFIG_NAME
-	string
 	default "nyan-big"
 
 endif

board/samsung/smdk5420/Kconfig

@@ -14,15 +14,12 @@ endif
 if TARGET_PEACH_PI
 
 config SYS_BOARD
-	string
 	default "smdk5420"
 
 config SYS_VENDOR
-	string
 	default "samsung"
 
 config SYS_CONFIG_NAME
-	string
 	default "peach-pi"
 
 endif

board/st/stv0991/Kconfig

 if TARGET_STV0991
 
-config SYS_CPU
-	string
-	default "armv7"
-
 config SYS_BOARD
-	string
 	default "stv0991"
 
 config SYS_VENDOR
-	string
 	default "st"
 
 config SYS_SOC
-	string
 	default "stv0991"
 
 config SYS_CONFIG_NAME
-	string
 	default "stv0991"
 
 endif

board/sunxi/Kconfig

@@ -33,7 +33,6 @@ config MACH_SUN8I
 endchoice
 
 config SYS_CONFIG_NAME
-	string
 	default "sun4i" if MACH_SUN4I
 	default "sun5i" if MACH_SUN5I
 	default "sun6i" if MACH_SUN6I