ARC: [Review] Multi-platform image #1: Kconfig enablement

This mini patchseries addresses the lack of multi-platform-image support
in ARC port.

Older build system only supported one platform(soc) to build at a time
and further only one board of that platform could be built. There was no
technical reason for that - we just didn't have the need.

So the first step towards multi-platform (and multi-board) builds it to
allow build system to do that.

So as applicable, <choice .. endchoice> => <menu .. endmenu>

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 2dab40d..3fdd6a5 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -82,9 +82,7 @@
 
 menu "ARC Architecture Configuration"
 
-choice
-	prompt "ARC Platform"
-	default ARC_PLAT_FPGA_LEGACY
+menu "ARC Platform/SoC"
 
 config ARC_PLAT_FPGA_LEGACY
 	bool "\"Legacy\" ARC FPGA dev platform"
@@ -96,7 +94,7 @@
 	  - MetaWare ISS
 
 #New platform adds here
-endchoice
+endmenu
 
 menu "ARC CPU Configuration"