tests/gem_mmap: Convert to subtests

I wanted to write a testcase for gtt mmap access restriction checking
and only noticed after conversion to subtests that this here is for
cpu mmaps ;-)

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

tests/Makefile.am

@@ -30,6 +30,7 @@ TESTS_progs_M = \
 	gem_flink \
 	gem_flink_race \
 	gem_linear_blits \
+	gem_mmap \
 	gem_mmap_gtt \
 	gem_partial_pwrite_pread \
 	gem_pread \
@@ -75,7 +76,6 @@ TESTS_progs = \
 	gem_hangcheck_forcewake \
 	gem_largeobject \
 	gem_lut_handle \
-	gem_mmap \
 	gem_mmap_offset_exhaustion \
 	gem_pin \
 	gem_pipe_control_store_loop \