drm/radeon: make VM size a module parameter (v2)

v2: agd5f: simplify patch

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --cc drivers/gpu/drm/radeon/radeon.h
Simple merge

diff --cc drivers/gpu/drm/radeon/radeon_device.c
Simple merge

diff --cc drivers/gpu/drm/radeon/radeon_drv.c
Simple merge