package/x11r7/xserver_xorg-server: dri needs arm >= v6

package/x11r7/xserver_xorg-server: dri needs arm >= v6

Fixes

  CC       dri.lo
/tmp/ccc6IbbW.s: Assembler messages:
/tmp/ccc6IbbW.s:3114: Error: selected processor does not support ARM mode `ldrex r2,[r1]'
/tmp/ccc6IbbW.s:3117: Error: selected processor does not support ARM mode `strexeq r2,r0,[r1]'
/tmp/ccc6IbbW.s:3273: Error: selected processor does not support ARM mode `ldrex r2,[r1]'
/tmp/ccc6IbbW.s:3276: Error: selected processor does not support ARM mode `strexeq r2,r3,[r1]'
/tmp/ccc6IbbW.s:3352: Error: selected processor does not support ARM mode `ldrex r1,[r2]'
/tmp/ccc6IbbW.s:3355: Error: selected processor does not support ARM mode `strexeq r1,r0,[r2]'
/tmp/ccc6IbbW.s:3451: Error: selected processor does not support ARM mode `ldrex r3,[r2]'
/tmp/ccc6IbbW.s:3454: Error: selected processor does not support ARM mode `strexeq r3,ip,[r2]'
/tmp/ccc6IbbW.s:3522: Error: selected processor does not support ARM mode `ldrex r3,[r0]'
/tmp/ccc6IbbW.s:3525: Error: selected processor does not support ARM mode `strexeq r3,r1,[r0]'
Makefile:653: recipe for target 'dri.lo' failed
make[5]: *** [dri.lo] Error 1
make[5]: Leaving directory '/home/buildroot/buildroot/output/build/xserver_xorg-server-1.17.2/hw/xfree86/dri'

using this defconfig
BR2_arm=y
BR2_TOOLCHAIN_BUILDROOT_WCHAR=y
BR2_TOOLCHAIN_BUILDROOT_CXX=y
BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_EUDEV=y
BR2_PACKAGE_MESA3D=y
BR2_PACKAGE_MESA3D_DRI_DRIVER_SWRAST=y
BR2_PACKAGE_XORG7=y
BR2_PACKAGE_XSERVER_XORG_SERVER=y

[Peter: fix conditional, add comment explaining issue]
Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>