EXYNOS5: DWMMC: Initialise the local variable to avoid unwanted results.

EXYNOS5: DWMMC: Initialise the local variable to avoid unwanted results.

This patch initialises the local variable 'shift' to zero.
The uninitialised local variable 'shift' had garbage value and was
resulting in unwnated results in the functions exynos5_get_mmc_clk()
and exynos4_get_mmc_clk().

Signed-off-by: Amar <amarendra.xt@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>