cpufreq/amd-pstate: Remove the unncecessary driver_lock in amd_pstate_update_limits

There is no need to take a driver wide lock while updating the
highest_perf value in the percpu cpudata struct. Hence remove it.

Signed-off-by: Dhananjay Ugwekar <dhananjay.ugwekar@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://lore.kernel.org/r/20250205112523.201101-13-dhananjay.ugwekar@amd.com


Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>