drm/amd/display: Add refresh rate range check

[Why]
We only enable the VRR while monitor usable refresh rate range
is greater than 10 Hz.
But we did not check the range in DRM_EDID_FEATURE_CONTINUOUS_FREQ
case.

[How]
Add a refresh rate range check before set the freesync_capable flag
in DRM_EDID_FEATURE_CONTINUOUS_FREQ case.

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>