Assume lpm display mode is supported

Since we now support proximity based fake lpm that does not
require special support from display hw / drivers, the logic
for mdy_low_power_mode_supported can be switched to: enabled
by default and disabled only in special cases.

[mce] Assume lpm display mode is supported. Fixes JB#19608
Merge pull request #173 from spiiroin/lpm_support

Assume lpm display mode is supported