disp: msm: dp: add 1.4a cts support for link training

Add support for new requirements in 1.4a CTS which need
to try link training 1 on different lane counts and link
rates.

CRs-Fixed: 2458753
Change-Id: I2039822f420a73232df7293afcddd7bee263c7b4
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>