package/arm-gnu-toolchain: add BR2_PACKAGE_HOST_ARM_GNU_TOOLCHAIN_SUPPORTS

ARM gnu toolchain for bare metal arm32 target is only available for
x86_64 and aarch64 hosts. Introduce a new option to disable packages
using this toolchain on unsupported hosts.

[Romain: improve commit log]
Signed-off-by: Bryce Johnson <bryce@redpinelabs.com>
Signed-off-by: Romain Naour <romain.naour@smile.fr>

package/Config.in.host

@@ -6,6 +6,7 @@ menu "Host utilities"
 	source "package/amlogic-boot-fip/Config.in.host"
 	source "package/andes-spi-burn/Config.in.host"
 	source "package/android-tools/Config.in.host"
+	source "package/arm-gnu-toolchain/Config.in.host"
 	source "package/asn1c/Config.in.host"
 	source "package/babeltrace2/Config.in.host"
 	source "package/bmap-tools/Config.in.host"

package/arm-gnu-toolchain/Config.in.host

@@ -0,0 +1,4 @@
+config BR2_PACKAGE_HOST_ARM_GNU_TOOLCHAIN_SUPPORTS
+	bool "host arm-gnu-toolchain"
+	default y if BR2_HOSTARCH = "aarch64"
+	default y if BR2_HOSTARCH = "x86_64"