phy: qcom-qusb2: Re add "qcom,sdm845-qusb2-phy" compat string

This patch fixes a regression in 5.7-rc1+

In commit 8fe75cd4 ("phy: qcom-qusb2: Add generic QUSB2 V2
PHY support"), the change was made to add "qcom,qusb2-v2-phy"
as a generic compat string. However the change also removed
the "qcom,sdm845-qusb2-phy" compat string, which is documented
in the binding and already in use.

This patch re-adds the "qcom,sdm845-qusb2-phy" compat string
which allows the driver to continue to work with existing dts
entries such as found on the db845c.

Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: Manu Gautam <mgautam@codeaurora.org>
Cc: Sandeep Maheswaram <sanm@codeaurora.org>
Cc: Matthias Kaehlcke <mka@chromium.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: linux-arm-msm@vger.kernel.org
Cc: devicetree@vger.kernel.org
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Fixes: 8fe75cd4 ("phy: qcom-qusb2: Add generic QUSB2 V2 PHY support")
Reported-by: YongQin Liu <yongqin.liu@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>