drm: samsung: add MIPI_CMD_SYNC_NONE to mipi_sync_mode

kms_properties test fails as bitmask property mipi_sync contains value zero.
So, MIPI_CMD_SYNC_NONE is introduced and used as the default value.

Bug: 263460552
Test: run kms_properties test
Change-Id: If12caeff31f853318e78bdb12eca5f580020cae4
Signed-off-by: Safayat Ullah <safayat@google.com>