cpufreq/amd-pstate-ut: Add fix for min freq unit test

cpufreq/amd-pstate-ut: Add fix for min freq unit test

commit 642aff3964b0f ("cpufreq/amd-pstate: Set the initial min_freq to
lowest_nonlinear_freq") changed the initial minimum frequency to lowest
nonlinear frequency, but the unit tests weren't updated and now fail.

Update them to match this same change.

Fixes: 642aff3964b0f ("cpufreq/amd-pstate: Set the initial min_freq to lowest_nonlinear_freq")
Link: https://lore.kernel.org/r/20241017173439.4924-1-mario.limonciello@amd.com
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>