ARM: dts: msm: Add override-bias-ctrl2 property

This property is added to override BIAS_CTRL2 value
from driver. If this property is set driver will override
BIAS_CTRL2 register else it will use the default value
passed from phy init sequence.

Change-Id: I8a428cf0a0099ca51aecf1f7bf6226925eae50ed
Signed-off-by: Pratham Pratap <prathampratap@codeaurora.org>