drm/amd/display: Initialize denominators' default to 1

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AZL-51354 CVE-2024-49899 affecting package kernel 5.15.200.1-1

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Initialize denominators' default to 1 WHAT & HOW Variables used as denominators and maybe not assigned to other values, should not be 0. Change their default to 1 so they are never 0. This fixes 10 DIVIDEBYZERO...