arm: socfpga: fix SPL on gen5 after moving to DM serial

There were NULL pointers dereferenced because DM was used
too early without correct initialization:
- malloc_simple returned NULL when called from preloader_console_init()
  because gd->malloc_limit was 0
- uclass_add dereferenced gd->uclass_root members which were NULL because
  dm_init (or one of its relatives) has not been called.

All this is fixed by calling spl_early_init before calling
preloader_console_init.

This fixes commit 73172753f4f3 ("ARM: socfpga: Convert to DM serial")

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>

arch/arm/mach-socfpga/spl_gen5.c

@@ -86,6 +86,7 @@ void board_init_f(ulong dummy)
 	const struct cm_config *cm_default_cfg = cm_get_default_config();
 	unsigned long sdram_size;
 	unsigned long reg;
+	int ret;
 
 	/*
 	 * First C code to run. Clear fake OCRAM ECC first as SBE
@@ -152,6 +153,12 @@ void board_init_f(ulong dummy)
 	/* unfreeze / thaw all IO banks */
 	sys_mgr_frzctrl_thaw_req();
 
+	ret = spl_early_init();
+	if (ret) {
+		debug("spl_early_init() failed: %d\n", ret);
+		hang();
+	}
+
 	/* enable console uart printing */
 	preloader_console_init();