arm: socfpga: fpga: Add SoCFPGA FPGA programming interface

Add code necessary to program the FPGA part of SoCFPGA from U-Boot
with an RBF blob. This patch also integrates the code into the
FPGA driver framework in U-Boot so it can be used via the 'fpga'
command.

Signed-off-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Chin Liang See <clsee@altera.com>
Cc: Dinh Nguyen <dinguyen@altera.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Tom Rini <trini@ti.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Pavel Machek <pavel@denx.de>

V2: Move the not-CPU specific stuff into drivers/fpga/ and base
    this on the cleaned up altera FPGA support.

drivers/fpga/altera.c

@@ -37,6 +37,9 @@ static const struct altera_fpga {
 	{ Altera_StratixII, "StratixII", StratixII_load,
 	  StratixII_dump, StratixII_info },
 #endif
+#if defined(CONFIG_FPGA_SOCFPGA)
+	{ Altera_SoCFPGA, "SoC FPGA", socfpga_load, NULL, NULL },
+#endif
 };
 
 static int altera_validate(Altera_desc *desc, const char *fn)