arch/alpha/kernel/smp.c: remove unnecessary (void*) conversions

The void * type pointer does not need to be cast and assigned to another
pointer.

Link: https://lkml.kernel.org/r/20221213074522.3738-1-zeming@nfschina.com


Signed-off-by: Li zeming <zeming@nfschina.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>