arm: samsung: Rename CONFIG_G_DNL_*_NUM variables

Following how g_dnl_bind_fixup is used on other platforms, rename the
unchanging defines used here to be prefixed with EXYNOS rather than
Samsung, and define them here.

Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Tom Rini <trini@konsulko.com>