msm: pcie: reduce RxEq training time for Gen3 core

Gen3 RxEq training is taking longer than needed. Therefore,
reduce the training time by updating Gen3 core configuration.

Change-Id: Ice0c3da3ed1d3e65858503334baa47b81baae88a
Signed-off-by: Tony Truong <truong@codeaurora.org>