Revert "msm: vidc: Use work mode 2 for avc encode with width > 3840"

This limitation is no longer necessary. UHD AVC usecase will work
with both work mode 1 and 2.

CRs-Fixed: 2285894
Change-Id: I0e1f0c79eee3335fac2c1eec75089eec6c63cdc8
Signed-off-by: Chinmay Sawarkar <chinmays@codeaurora.org>