CI: use path to avoid warning

Warnings are being seen in gitlab of
 WARNING  - Falling back to file-relative addressing of local include "base.yml"
 WARNING  - Update your layer to repo-relative addressing to avoid this warning
 WARNING  - Falling back to file-relative addressing of local include "meta-openembedded.yml"
 WARNING  - Update your layer to repo-relative addressing to avoid this warning

Make the relevant changes to resolve this issue

Signed-off-by: Jon Mason <jon.mason@arm.com>
Signed-off-by: Naveen Saini <naveen.kumar.saini@intel.com>

ci/96b-avenger96.yml

 header:
   version: 9
   includes:
-    - base.yml
+    - ci/base.yml
 
 machine: 96b-avenger96

ci/96b-nitrogen.yml

 header:
   version: 9
   includes:
-    - base.yml
+    - ci/base.yml
 
 machine: 96b-nitrogen

ci/arduino-nano-33-ble.yml

 header:
   version: 9
   includes:
-    - base.yml
+    - ci/base.yml
 
 machine: arduino-nano-33-ble

ci/base.yml

 header:
   version: 11
   includes:
-    - meta-openembedded.yml
+    - ci/meta-openembedded.yml
 
 distro: zephyr
 

ci/intel-x86-64.yml

 header:
   version: 9
   includes:
-    - base.yml
+    - ci/base.yml
 
 machine: intel-x86-64

ci/nrf52840dk-nrf52840.yml

 header:
   version: 9
   includes:
-    - base.yml
+    - ci/base.yml
 
 machine: nrf52840dk-nrf52840

ci/qemu-nios2.yml

 header:
   version: 9
   includes:
-    - base.yml
+    - ci/base.yml
 
 local_conf_header:
   nonbuilding_tests: |

ci/qemu-x86.yml

 header:
   version: 9
   includes:
-    - base.yml
+    - ci/base.yml
 
 local_conf_header:
   failing_tests: |

ci/stm32mp157c-dk2.yml

 header:
   version: 9
   includes:
-    - base.yml
+    - ci/base.yml
 
 machine: stm32mp157c-dk2