drm/i915/alpm: Enable lobf from source in ALPM_CTL

drm/i915/alpm: Enable lobf from source in ALPM_CTL

Set the Link Off Between Frames Enable bit in ALPM_CTL register.

Note: Lobf need to be enabled adaptive sync fixed refresh mode
where vmin = vmax = flipline, which will arise after cmmr feature
enablement. Will add enabling sequence in a separate patch.

v1: Initial version.
v2: Condition check modified in alpm_configure(). [Jouni]

Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240529200742.1694401-6-animesh.manna@intel.com