ARM: EXYNOS4: Fix wrong pll type for vpll

The PLL4650C is used for VPLL on EXYNOS4 so should be fixed.

Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com>
[kgene.kim@samsung.com: added message]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>