macintosh/via-pmu: Fix section mismatch warning

The pmu_init() function has the __init qualifier, but the ops struct
that holds a pointer to it does not. This causes a build warning.
The driver works fine because the pointer is only dereferenced early.

The function is so small that there's negligible benefit from using
the __init qualifier. Remove it to fix the warning, consistent with
the other ADB drivers.

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>