exynos: spl: Add a custom spi copy function

exynos: spl: Add a custom spi copy function

This patch implements a custom spi_copy funtion to copy u-boot from SF
to RAM. This is faster then iROM spi_copy funtion as this runs spi at
50Mhz and also in WORD mode of operation.

Changed a printf in pinmux.c to debug just to avoid the compilation
error in SPL.

Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Tom Wai-Hong Tam <waihong@chromium.org>
Signed-off-by: Rajeshwari S Shinde <rajeshwari.s@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>