phy: qcom-qmp: Use register defines

We already define register offsets so use them in register layout.

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Manu Gautam <mgautam@codeaurora.org>
Reviewed-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>