wifi: iwlwifi: mld: start AP with the correct bandwidth

wifi: iwlwifi: mld: start AP with the correct bandwidth

When a channel context is added, it is still not assigned to the link
and the link is not yet active. As a result, the channel context
min_def is used when the AP is started, even when the full bandwidth
should be used.
Fix it by updating the PHY channel context when the link is already
active so the full bandwidth is used when needed.

Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250430155443.30b043b10fb1.I62c2aa58687e4796b759fa68132122119a337b49@changeid