x86/PCI: Make a kernel-doc comment a normal one

The comment is using kernel-doc markup but that comment isn't a
kernel-doc comment so make it a normal one to avoid:

  arch/x86/pci/i386.c:373: warning: Function parameter or member \
	  'pcibios_assign_resources' not described in 'fs_initcall'

 [ bp: Massage and fixup comment while at it. ]

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/1605257895-5536-5-git-send-email-alex.shi@linux.alibaba.com