iwlwifi: mvm: fix some kerneldoc issues

A few fields were missing their kerneldoc in the station
capabilities.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Fixes: c8a2e7a2 ("iwlwifi: sta: set max HE max A-MPDU according to HE capa")
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20211024165252.fecbcd7c2fcc.I7419f102b798ba0cecd93c80f345b241670e0683@changeidSigned-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/fw/api/sta.h

@@ -28,6 +28,8 @@
  * @STA_FLG_MAX_AGG_SIZE_256K: maximal size for A-MPDU (256k supported)
  * @STA_FLG_MAX_AGG_SIZE_512K: maximal size for A-MPDU (512k supported)
  * @STA_FLG_MAX_AGG_SIZE_1024K: maximal size for A-MPDU (1024k supported)
+ * @STA_FLG_MAX_AGG_SIZE_2M: maximal size for A-MPDU (2M supported)
+ * @STA_FLG_MAX_AGG_SIZE_4M: maximal size for A-MPDU (4M supported)
  * @STA_FLG_AGG_MPDU_DENS_MSK: maximal MPDU density for Tx aggregation
  * @STA_FLG_FAT_EN_MSK: support for channel width (for Tx). This flag is
  *	initialised by driver and can be updated by fw upon reception of