staging: rtl8712: Fix possible buffer overrun

staging: rtl8712: Fix possible buffer overrun

In commit ef8a579546c5 ("staging: r8712u: Fix possible buffer
overrun") we fix a potential off by one by making the limit smaller.
The better fix is to make the buffer larger.  This makes it match up
with the similar code in other drivers.

Fixes: ef8a579546c5 ("staging: r8712u: Fix possible buffer overrun")
Signed-off-by: Young Xiao <YangX92@hotmail.com>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>