staging: rtl8723bs: hal: Remove unnecessary typecast in kfree.

Remove typecast in the call to kfree as it is not needed.
Issue fixed using Coccinelle.

Signed-off-by: Nachammai Karuppiah <nachukannan@gmail.com>
Link: https://lore.kernel.org/r/1572973591-12892-1-git-send-email-nachukannan@gmail.com


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