package/gcc: properly handle legacy for renamed ARC option

Commit "50332a530b gcc: rename option for ARC gcc" tried to add legacy
handling but the new symbol is part of a choice, and Kconfig does not
enforce the select of a option from a choice.

Update the legacy entry for 2016.11, following the example described in
the beginning of the file.

Cc: Giulio Benetti <giulio.benetti@benettiengineering.com>
Cc: Romain Naour <romain.naour@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit eb8f38891b16e5fb0f010c658b271e22670a1633)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

Config.in.legacy

@@ -3809,10 +3809,11 @@ config BR2_LINUX_KERNEL_TOOL_SELFTESTS
 config BR2_GCC_VERSION_4_8_ARC
 	bool "gcc arc option renamed"
 	select BR2_LEGACY
-	select BR2_GCC_VERSION_ARC
 	help
 	  The option that selects the gcc version for the ARC
 	  architecture has been renamed to BR2_GCC_VERSION_ARC.
+# Note: BR2_GCC_VERSION_4_8_ARC is still referenced from
+# package/gcc/Config.in.host
 
 config BR2_KERNEL_HEADERS_4_0
 	bool "kernel headers version 4.0.x are no longer supported"

package/gcc/Config.in.host

@@ -2,6 +2,7 @@ comment "GCC Options"
 
 choice
 	prompt "GCC compiler Version"
+	default BR2_GCC_VERSION_ARC if BR2_GCC_VERSION_4_8_ARC # legacy
 	default BR2_GCC_VERSION_ARC if BR2_arc
 	default BR2_GCC_VERSION_POWERPC_SPE if BR2_powerpc_SPE
 	default BR2_GCC_VERSION_10_X