ARM: SAMSUNG: Use debug_ll_addr() to get UART base address

This patch modifies Samsung PM debug helpers to use a multiplatform
friendly way of getting base address of debug UART port, so instead
of using a per-mach static macro, a generic debug_ll_addr() helper
is used.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>