ACPI: CPPC: Replace ternary operator with umax()

Replace ternary operator with umax() in cppc_find_dmi_mhz().

Signed-off-by: Prabhakar Pujeri <prabhakar.pujeri@gmail.com>
[ rjw: Subject and changelog edits ]
Link: https://patch.msgid.link/20240626130941.1527127-2-prabhakar.pujeri@gmail.com


Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>