cpufreq: amd-pstate: Don't create attributes when registration fails

If driver registration fails then immediately return the failure
instead of continuing to register attributes.

This fixes issues of falling back from amd-pstate to other drivers
when cpufreq init has failed for any reason.

Reported-by:  <alex.s.cochran@proton.me>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Reviewed-by: Perry Yuan <Perry.Yuan@amd.com>
Link: https://lore.kernel.org/r/20240623200918.52104-1-mario.limonciello@amd.com


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