staging: rtl8723bs: fix typo of "mechanism" in comment

Fix typo s/mechansim/mechanism/

Signed-off-by: Antonio Borneo <antonio.borneo@st.com>
Link: https://lore.kernel.org/r/20191007154306.95827-2-antonio.borneo@st.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>