This patch fixes memory alloction(contiguous or not) and
cache mapping types(cachable or not).
For this, it converts each type from user request into dma
attribute properly.

Changelog v2:
- just code cleanup.
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>