common: Pass the boot device into spl_boot_mode()

The SPL code already knows which boot device it calls the spl_boot_mode()
on, so pass that information into the function. This allows the code of
spl_boot_mode() avoid invoking spl_boot_device() again, but it also lets
board_boot_order() correctly alter the behavior of the boot process.

The later one is important, since in certain cases, it is desired that
spl_boot_device() return value be overriden using board_boot_order().

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Andreas Bießmann <andreas.devel@googlemail.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Tom Rini <trini@konsulko.com>
Reviewed-by: Andreas Bießmann <andreas@biessmann.org>
[add newly introduced zynq variant]
Signed-aff-by: Andreas Bießmann <andreas@biessmann.org>
diff --git a/arch/arm/mach-zynq/spl.c b/arch/arm/mach-zynq/spl.c
index 6c5415a..e8added 100644
--- a/arch/arm/mach-zynq/spl.c
+++ b/arch/arm/mach-zynq/spl.c
@@ -69,7 +69,7 @@
 }
 
 #ifdef CONFIG_SPL_MMC_SUPPORT
-u32 spl_boot_mode(void)
+u32 spl_boot_mode(const u32 boot_device)
 {
 	return MMCSD_MODE_FS;
 }