Fix hostapd obss_interval documentation

This parameter has been available for more than just testing purposes,
i.e., OBSS scanning has already been used to enable 20-to-40 MHz channel
changes on 2.4 GHz.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

hostapd/hostapd.conf

@@ -494,9 +494,9 @@ wmm_ac_vo_acm=0
 
 # If set non-zero, require stations to perform scans of overlapping
 # channels to test for stations which would be affected by 40 MHz traffic.
-# This parameter sets the interval in seconds between these scans. This
-# is useful only for testing that stations properly set the OBSS interval,
-# since the other parameters in the OBSS scan parameters IE are set to 0.
+# This parameter sets the interval in seconds between these scans. Setting this
+# to non-zero allows 2.4 GHz band AP to move dynamically to a 40 MHz channel if
+# no co-existence issues with neighboring devices are found.
 #obss_interval=0
 
 ##### IEEE 802.11ac related configuration #####################################