arm: sunxi: Move spl spi sunxi code to mach-sunxi

This SUNXI variant SPL SPI code doesn't use either SPI or
SPL_FLASG subsystems due to size constraints and also placing
this code in drivers/mtd/spi will unnecessary build SPI_FLASH
code(if defined) which never required, hence moved to arch area.

And also renamed the file according to kconfig which resembles
proper name.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig
index 1fededd..dc48eef 100644
--- a/arch/arm/mach-sunxi/Kconfig
+++ b/arch/arm/mach-sunxi/Kconfig
@@ -847,4 +847,12 @@
 	default 0x2fe00000 if MACH_SUN9I
 	default 0x4fe00000 if MACH_SUN50I
 
+config SPL_SPI_SUNXI
+	bool "Support for SPI Flash on Allwinner SoCs in SPL"
+	depends on MACH_SUN4I || MACH_SUN5I || MACH_SUN7I || MACH_SUNXI_H3_H5 || MACH_SUN50I
+	help
+	  Enable support for SPI Flash. This option allows SPL to read from
+	  sunxi SPI Flash. It uses the same method as the boot ROM, so does
+	  not need any extra configuration.
+
 endif