Staging: sxg: Add support to download the firmware using request_firmware()

Add support for downloading the firmware using kernel-builtin mechanism.
This will remove the need for the firmware files in the driver source code.

Signed-off-by: Christopher Harrer <charrer@alacritech.com>
Signed-off-by: Mithlesh Thukral <mithlesh@linsyssoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

firmware/WHENCE

@@ -378,6 +378,18 @@ Found in hex form in kernel source.
 
 --------------------------------------------------------------------------
 
+Driver: SXG - Alacritech IS-NIC products
+
+File: sxg/saharadownloadB.sys.ihex
+File: sxg/saharadbgdownloadB.sys.ihex
+
+Licence: Unknown
+
+Found in hex form in kernel source.
+Copyright 1997-2009 Alacritech, Inc. All rights reserved.
+
+--------------------------------------------------------------------------
+
 Driver: cxgb3 - Chelsio Terminator 3 1G/10G Ethernet adapter
 
 File: cxgb3/t3b_psram-1.1.0.bin.ihex