rtlwifi: rtl8192se firmware load can overflow target buffer

Define RTL8190_MAX_RAW_FIRMWARE_CODE_SIZE which represents the
maximimum possible firmware file size. Use it in the definition
of the buffer which receives the firmware file data.

Set RTL8190_MAX_RAW_FIRMWARE_CODE_SIZE closer to the actual size of
the firmware file, e.g., 90000 (down from hard coded 164000). The current
size of rtlwifi/rtl8192sefw.bin is 88856.

Set max_fw_size to RTL8190_MAX_RAW_FIRMWARE_CODE_SIZE for the size limit
check. Fix the error case where max_fw_size is not cleared if the size
limit check fails.

Cc: Chaoming Li <chaoming_li@realsil.com.cn>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>