Revert "ARM: SPL: do not set gd again"

At the high level, the problem is that we set gd multiple times (and
still do, even after the commit we're reverting).  We set important
parts of gd to the copy which is not above stack but rather in the data
section.  For the release, we're going to revert this change and for the
next release we shall correct things to only, really, set gd once to an
appropriate location and ensure that comments about it are correct too.

This reverts commit f0c3a6c4.

Acked-by: Albert Aribaud <albert.u.boot@aribaud.net>
Signed-off-by: Tom Rini <trini@ti.com>

arch/arm/lib/spl.c

@@ -28,6 +28,9 @@ void __weak board_init_f(ulong dummy)
 	/* Clear the BSS. */
 	memset(__bss_start, 0, __bss_end - __bss_start);
 
+	/* Set global data pointer. */
+	gd = &gdata;
+
 	board_init_r(NULL, 0);
 }