clk: exynos4: Define {E,V}PLL registers

This patch adds preprocessor definitions of EPLL and VPLL registers and
replaces all occurences of offsets of related registers with new
definitions.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>