spl: consolidate arch/arm/include/asm/arch-*/spl.h

spl: consolidate arch/arm/include/asm/arch-*/spl.h

arch/arm/include/asm/spl.h requires all SoCs to have
arch/arm/include/asm/arch-*/spl.h.

But many of them just define BOOT_DEVICE_* macros.

Those macros are used in the "switch (boot_device) { ... }"
statement in common/spl/spl.c.

So they should not be archtecture specific, but be described as
a simpile enumeration.

This commit merges most of arch/arm/include/asm/arch-*/spl.h
into arch/arm/include/asm/spl.h.

With a little more effort, arch-zynq/spl.h and arch-socfpga/spl.h
will be merged, while I am not sure about OMAP and Exynos.

Signed-off-by: Masahiro Yamada <[email protected]>
Cc: Tom Rini <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Andreas Bießmann <[email protected]>
Cc: Stephen Warren <[email protected]>
Cc: Tom Warren <[email protected]>
CC: Stefano Babic <[email protected]>
CC: Minkyu Kang <[email protected]>
Cc: Dinh Nguyen <[email protected]>
Acked-by: Andreas Bießmann <[email protected]>
Acked-by: Michal Simek <[email protected]>
Acked-by: Stefano Babic <[email protected]>
Acked-by: Stephen Warren <[email protected]>
Acked-by: Tim Harvey <[email protected]>
Tested-by: Bo Shen <[email protected]> [on sama5d3xek board for at91 part]
Acked-by: Stephen Warren <[email protected]>
Tested-by: Stefano Babic <[email protected]> [applying Tim's i.MX6 patches]
Acked-by: Tom Rini <[email protected]>