msm: pcie: support tuning of minimum time spent in EQ Master Phase

During Gen3 and Gen4 link training, PCIe PHY may require
additional time during the equalization master phase before
proceeding to the next LTSSM state. Add the support to configure
the minimum amount of time spent during equalization master
phase.

Change-Id: Id3e7ff631f6ce004829065ad798223d7d774edc1
Signed-off-by: Tony Truong <truong@codeaurora.org>