board-latona: BT runtime PM adaptation

Add UART enable/disable functions in board file to control UART
clks from wilink chip sleep/awake/enable/disable functions.

Signed-off-by: David Rodero <david@codiguiel.net>
board-latona: hold wake lock on WiLink awake

AVRCP Play/Pause when screen is lit off causing resume/suspend. Several trials of such
suspend and resume causes the AVRCP/Media Player to stop streaming to BT headset upon
one of such suspend iterations.

By holding a wake-lock when WiLink is AWAKE and releasing it when ASLEEP, we provide
enough time for MediaPlayer to process/resume Play/Pause operation.

Signed-off-by: David Rodero <david@codiguiel.net>
mach: opp: use dpll3_m2_ck as reference clock for L3

l3_ick has a max rate of 200MHz only.

Signed-off-by: David Rodero <david@codiguiel.net>