PCI: qcom: Add support for tx term offset for rev 2.1.0

PCI: qcom: Add support for tx term offset for rev 2.1.0

Add tx term offset support to pcie qcom driver need in some revision of
the ipq806x SoC. Ipq8064 needs tx term offset set to 7.

Link: https://lore.kernel.org/r/20200615210608.21469-9-ansuelsmth@gmail.com
Fixes: 82a823833f4e ("PCI: qcom: Add Qualcomm PCIe controller driver")
Signed-off-by: Sham Muthayyan <smuthayy@codeaurora.org>
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Stanimir Varbanov <svarbanov@mm-sol.com>
Cc: stable@vger.kernel.org # v4.5+