ACPI: CPPC: Drop check for non zero perf ratio

perf_ratio is a u64 and SCHED_CAPACITY_SCALE is a large number.
Shifting by one will never have a zero value.

Drop the check.

Suggested-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.sheoy@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>