Staging: rtl8188eu: core: Fix coding style issue

This fixes the following checkpatch.pl warning
WARNING: Prefer using '"%s...", __func__' to using 'rtw_tkip_decrypt', this function's name, in a string.

Signed-off-by: Anoop S <anoop.skumar1507@gmail.com>
Link: https://lore.kernel.org/r/20200718103125.62528-1-anoop.skumar1507@gmail.com


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