btf: re-enable apt pahole wrapper for hermetic BTF generation

Run 31246574823 (after 0001+0002+dd re-enabled) fails at BTFIDS with
'FAILED unresolved symbol xdp_buff' on every completed android12-5.10
job, right after the prebuilt pahole v1.19 floods
tag__recode_dwarf_type 'couldn't find' warnings during BTF gen — the
known 1.19 recode bug that drops struct xdp_buff from vmlinux BTF.
Re-enable the step that replaces the hermetic prebuilt pahole with a
wrapper exec'ing apt pahole (>=1.23, installed on the runner) plus
--skip_encoding_btf_enum64/decl_tag/type_tag for the old in-tree
libbpf. Remaining disabled: 0003 (xdp_buff BTF-emit), 0004
(ELF_T_WORD).

.github/actions/btf/action.yml

@@ -88,7 +88,7 @@ runs:
     - name: Use apt pahole (>=1.23) for hermetic BTF generation (android12-5.10)
       shell: bash
       working-directory: ${{ github.workspace }}/kernel
-      if: false
+      if: ${{ inputs.version == 'android12-5.10' }}
       run: |
         set -euo pipefail
         # android12-5.10 pins prebuilt pahole v1.19, which fails to recode the