ARM: dts: msm: Add DEBUG_CTRL1 register in qusb_phy on SDM670

This register is added to qusb_phy so that driver can override
the value based on SoC version.

Change-Id: I5142930a5edd3e7df783169c03c4360a0aed7672
Signed-off-by: Pratham Pratap <prathampratap@codeaurora.org>