drm/amd/display: Avoid divide by zero by initializing dummy pitch to 1

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Avoid divide by zero by initializing dummy pitch to 1 [Why] If the dummy values in `populate_dummy_dml_surface_cfg()` aren't updated then they can lead to a divide by zero in downstream callers like CalculateVMAndRowBytes() [How] Initialize dummy value to a value to avoid divide by zero.

References

• https://git.kernel.org/stable/c/8044f981b2cf8c32fe1bd5d1fc991552cdf7ffe0
• https://git.kernel.org/stable/c/7e40f64896e8e3dca471e287672db5ace12ea0be