Enable simple_block_yrd for temporal enhancement layers (TL > 0).
And remove block size condiiton for SVC mode.
Only affects speed >= 7 SVC.

Speedup ~3-4%.
avgPSNR regression on RTC for (3 spatial, 3 temporal) layers: ~1%.

Change-Id: Iff4fc191623b71c69cd373e7c0823385e7ac67ed