usb: pd: Increase number of SRC_CAP attempts before starting host

It is observed that some PD-capable sink devices have a
longer start-up delay before responding to the Source
Capabilities message with a Request. Since it is PD capable
we'd like to wait until after entering PE_SRC_Ready and VDM
Discovery to start USB host mode. Accommodate these devices by
increasing the number of failed attempts of sending the message
from 5 to 10 before treating it as a non-PD device and starting
host mode.

Change-Id: Ia555699e78729b75dc118cbb929f7c4c4f2d1279
Signed-off-by: Jack Pham <jackp@codeaurora.org>