utils/genrandconfig: add default setting for bare-metal toolchain arch

We recently added support for building a bare-metal toolchain, and the
autobuilders are therefore trying to build such toolchains. However,
by default the BR2_TOOLCHAIN_BARE_METAL_BUILDROOT_ARCH option is
empty, causing the target tuple to be empty, and therefore
host-gcc-bare-metal tries to build a toolchain for the target
"x86_64-pc-linux-gnu", which isn't a bare-metal target, and fails
badly.

In order to properly test this bare-metal support, this commit adjusts
the genrandconfig script so that it injects a valid target
architecture tuple.

Fixes:

  http://autobuild.buildroot.net/results/6cb1514b19bfe056fb984d3538bdccdda5e174c1/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

utils/genrandconfig

@@ -315,6 +315,10 @@ def fixup_config(sysinfo, configfile):
        'BR2_TOOLCHAIN_BUILDROOT=y' in configlines:
         return False
 
+    if 'BR2_TOOLCHAIN_BARE_METAL_BUILDROOT=y' in configlines:
+        configlines.remove('BR2_TOOLCHAIN_BARE_METAL_BUILDROOT_ARCH=""')
+        configlines.add('BR2_TOOLCHAIN_BARE_METAL_BUILDROOT_ARCH="microblazeel-xilinx-elf"')
+
     if 'BR2_PACKAGE_AUFS_UTIL=y\n' in configlines and \
        'BR2_PACKAGE_AUFS_UTIL_VERSION=""\n' in configlines:
         return False