arm: dra7: Set fastboot variables in environment

One can obtain those variables using next commands:

    $ fastboot getvar cpu
    $ fastboot getvar secure
    $ fastboot getvar board_rev
    $ fastboot getvar userdata_size

Those variables are needed for fastboot.sh script.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/board/ti/dra7xx/evm.c b/board/ti/dra7xx/evm.c
index 8c02add..7d36f03 100644
--- a/board/ti/dra7xx/evm.c
+++ b/board/ti/dra7xx/evm.c
@@ -561,6 +561,7 @@
 		setenv("boot_fit", "1");
 
 	omap_die_id_serial();
+	omap_set_fastboot_vars();
 #endif
 	return 0;
 }