west.yml: update Zephyr to ceff785434b

Patches affecting SOF:

fb54eb5ab133 llext: symbol.h: Explicit typecast in EXPORT_SYMBOL macros
ce243944375e llext: add object test case
33c6bdab9ad1 llext: add STT_OBJECT relocation
41b3c7158687 drivers: dma: intel_adsp_hda: Fix L1 exit condition
5cac834bb651 llext: arch_elf_relocate: pass opval unmodified

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

west.yml

@@ -43,7 +43,7 @@ manifest:
 
     - name: zephyr
       repo-path: zephyr
-      revision: 251f52cbceb8a1682233c1792cbe68d28676318c
+      revision: ceff785434b970a4570d82023dc136ef8a050f3f
       remote: zephyrproject
 
       # Import some projects listed in zephyr/west.yml@revision