EDAC, sb_edac: Get rid of ->show_interleave_mode()

Function sbridge_register_mci() sets pvt->info.show_interleave_mode
to knl_show_interleave_mode() on Knight's Landing and
show_interleave_mode() anywhere else.

Merge show_interleave_mode() and knl_show_interleave_mode() in a single
implementation and use it without an indirect function pointer.

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170122172806.10412-1-nicolas.iooss_linux@m4x.org


[ Call it get_intlv_mode_str(). ]
Signed-off-by: Borislav Petkov <bp@suse.de>