mwifiex: fix typo in RSSI_HIGH event handling

This is a copy-n-paste error introduced in recent patch
"mwifiex: add set_cqm_rssi_config handler support".

Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>