media: aspeed: Add macro for the fields of the mode-detect registers

VE_MODE_DT_HOR_TOLER: the tolerance in detecting for stable horizontal
signal.
VE_MODE_DT_VER_TOLER: the tolerance in detecting for stable vertical
signal.
VE_MODE_DT_HOR_STABLE: the minimum required count in detecting stable
HSYNC signal to set mode detection horizontal signal stable.
VE_MODE_DT_VER_STABLE: the minimum required count in detecting stable
VSYNC signal to set mode detection vertical signal stable.

Signed-off-by: Jammy Huang <jammy_huang@aspeedtech.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>