wifi: iwlwifi: pcie: remove constant wdg_timeout

This value is only ever initialized and read, so just
replace the usage with the constant and remove it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250503224232.48333e80a74d.I6c1aaa23fac5ff7400aa59a3093b53774261cb0e@changeid