iwlwifi: import two fixes from linux v5.18-rc7

Import two changes from torvalds/linux.git at tag: v5.18-rc7:
b20bdd9cc9740ac1f2138adab25ddd51245c67be

iwlwifi: mvm: Don't fail if PPAG isn't supported

7635a1ad8d92dcc8247b53f949e37795154b5b6f

iwlwifi: iwl-dbg: Use del_timer_sync() before freeing

Sponsored by: The FreeBSD Foundation

(cherry picked from commit 88a15f72cf6b4e80688daf56a7ac493999f25ccd)