ARM: EXYNOS: use v7_exit_coherency_flush macro for cache disabling

ARM: EXYNOS: use v7_exit_coherency_flush macro for cache disabling

A common macro v7_exit_coherency_flush available which does the below
tasks in the seqeunce.
-clearing C bit
-clearing L1 cache
-exit SMP
-instruction and data synchronization

So removing the local functions which does the same thing and use the
macro instead.

Signed-off-by: Leela Krishna Amudala <[email protected]>
Acked-by: Nicolas Pitre <[email protected]>
[[email protected]: tested on exynos3250 based board]
Tested-by: Chanwoo Choi <[email protected]>
Signed-off-by: Kukjin Kim <[email protected]>