MLK-14720 epdc: correct WFE setting when bypass legacy process

MLK-14720 epdc: correct WFE setting when bypass legacy process

set WFE (WFE_A on imx7d, and WFE_B on imx6ull/imx6sll) input address to
framebuffer start address, and set left/top coordinate since the framebuffer is
the original source of WFE (i.e., not from PXP output) when bypass legacy mode.
The patch also limits the condition to bypass legacy mode when not use
EPDC_FLAG_USE_ALT_BUFFER.

Signed-off-by: Robby Cai <robby.cai@nxp.com>
(cherry picked from commit 7f19940705902623166777c675f5e10c9e7fc477)
Signed-off-by: Arulpandiyan Vadivel <arulpandiyan_vadivel@mentor.com>