ci/freedreno: Rebalance limozeen jobs

We have 6 DUTs but we are running a total of 7 jobs per pipeline,
increasing the DUT pending time.

- Job: parallel no.
- 'a618_gl: 2'
- 'a618_egl: 1'
- 'a618_piglit: 1'
- 'zink-tu-a618: 1'

So, reduce the `a618_gl` parallel from 2 to 1 and increase dEQP fraction
from 2 to 5 to reach the 10-min mark.

Signed-off-by: Guilherme Gallo <guilherme.gallo@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31699>

src/freedreno/ci/gitlab-ci.yml

@@ -110,11 +110,10 @@ a618_gl:
     - .lava-test-deqp:arm64
     - .lava-sc7180-trogdor-lazor-limozeen:arm64
     - .collabora-freedreno-rules
-  parallel: 2
   variables:
     DEQP_SUITE: freedreno-a618
     FLAKES_CHANNEL: "#freedreno-ci"
-    DEQP_FRACTION: 2
+    DEQP_FRACTION: 4
 
 a618_gl_full:
   extends: