SMDK5250: Initialise and Enable DWMMC, support FDT and non-FDT

SMDK5250: Initialise and Enable DWMMC, support FDT and non-FDT

This patch enables and initialises DWMMC for SMDK5250.
Supports both FDT and non-FDT. This patch creates a new file
'exynos5-dt.c' meant for FDT support.
        exynos5-dt.c:   This file shall contain all code which supports FDT.
                        Any addition of FDT support for any module needs to be
                        added in this file.
        smdk5250.c:     This file shall contain the code which supports non-FDT.
                        version. Any addition of non-FDT support for any module
                        needs to be added in this file.
                        May be, the file smdk5250.c can be removed in near future
                        when non-FDT is not required.

The Makefile is updated to compile only one of the files
exynos5-dt.c / smdk5250.c based on FDT configuration.

NOTE:
Please note that all additions corresponding to FDT need to be added into the
file exynos5-dt.c.
At same time if non-FDT support is required then add the corresponding
updations into smdk5250.c.

Signed-off-by: Amar <amarendra.xt@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>