atv_demod: switch channel with the script, the ATV shows no signal [1/1]

atv_demod: switch channel with the script, the ATV shows no signal [1/1]

PD#SWPL-791

Problem:
Switch channel with the script lasts 14 hours, the ATV shows no signal.

Solution:
To avoid conflict, don't need to check the CLK
and PLL states in atv demod write and read function.

Verify:
verified by p321

Change-Id: I033c54f14541ed540dfce1b9c4e21d2b5a8b9487
Signed-off-by: nengwen.chen <nengwen.chen@amlogic.com>