glmark2: don't build drm flavours for machines not supporting it
imx-gpu-viv_6.4.0.p1.0-aarch32 does not provide virtual/libgbm and thus
a build with drm* in PACKAGECONFIG does fail.
Thus remove drm* from PACKAGECONFIG for those machines.
| ERROR: Nothing PROVIDES 'virtual/libgbm' (but .../glmark2_git.bb DEPENDS on or otherwise requires it)
| gpulib PROVIDES virtual/libgbm but was skipped: incompatible with machine
fixes:
7801868f glmark2: Remove bbappend
Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
