wifi: iwlwifi: mvm: calculate EMLSR mode after connection

The function iwl_mvm_can_enter_esr() is (among others) calculating
if EMLSR mode is disabled due to BT coex by calling
iwl_mvm_bt_coex_calculate_esr_mode(), then stores the decision in
mvmvif::esr_disable_reason.
But there is no need to calculate this every time iwl_mvm_can_enter_esr
is called. Fix this by calculating it once after authorization,
and in iwl_mvm_can_enter_esr only check mvmvif::esr_disable_reason.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240416134215.a767e243366e.I3b32d36cda23f67dc103a28a9bdccb0039d22574@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>