misc: ocxl: afu_irq: Remove unnecessary (void*) conversions

The irq pointer does not need to cast the type.

Signed-off-by: Li zeming <zeming@nfschina.com>
Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231113012202.7887-1-zeming@nfschina.com