macintosh: Use common error handling code in via_pmu_led_init()

Add a jump target so that a bit of exception handling can be better reused
at the end of this function implementation.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/189b93e2-4e81-438d-9c77-cbe4d9d7a0d9@web.de