wifi: mwifiex: Fix a loop in mwifiex_update_ampdu_rxwinsize()

wifi: mwifiex: Fix a loop in mwifiex_update_ampdu_rxwinsize()

The "i" iterator variable is used to count two different things but
unfortunately we can't store two different numbers in the same variable.
Use "i" for the outside loop and "j" for the inside loop.

Cc: stable@vger.kernel.org
Fixes: d219b7eb3792 ("mwifiex: handle BT coex event to adjust Rx BA window size")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Jeff Chen <jeff.chen_1@nxp.com>
Link: https://patch.msgid.link/aWAM2MGUWRP0zWUd@stanley.mountain
Signed-off-by: Johannes Berg <johannes.berg@intel.com>