EDAC/sifive: Fix non-kernel-doc comment

scripts/kernel-doc complains about a comment that begins with "/**"
but is not in kernel-doc format, so correct it.

Prevents this warning:

drivers/edac/sifive_edac.c:23: warning: This comment starts with '/**', \
but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* EDAC error callback

Fixes: 91abaeaaff35 ("EDAC/sifive: Add EDAC platform driver for SiFive SoCs")
Reported-by: kernel test robot <[e-mail]>
Signed-off-by: Randy Dunlap <[e-mail]>
Signed-off-by: Borislav Petkov <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/edac/sifive_edac.c

···
 	struct edac_device_ctl_info *dci;
 };
 
-/**
+/*
  * EDAC error callback
  *
  * @event: non-zero if unrecoverable.