edac_mc: Cleanup per-dimm_info debug messages

The edac_mc_alloc() routine allocates one dimm_info device for all
possible memories, including the non-filled ones. The debug messages
there are somewhat confusing. So, cleans them, by moving the code
that prints the memory location to edac_mc, and using it on both
edac_mc_sysfs and edac_mc.

Also, only dumps information when DIMM/ranks are actually
filled.

After this patch, a dimm-based memory controller will print the debug
info as:

[ 1011.380027] EDAC DEBUG: edac_mc_dump_csrow: csrow->csrow_idx = 0
[ 1011.380029] EDAC DEBUG: edac_mc_dump_csrow:   csrow = ffff8801169be000
[ 1011.380031] EDAC DEBUG: edac_mc_dump_csrow:   csrow->first_page = 0x0
[ 1011.380032] EDAC DEBUG: edac_mc_dump_csrow:   csrow->last_page = 0x0
[ 1011.380034] EDAC DEBUG: edac_mc_dump_csrow:   csrow->page_mask = 0x0
[ 1011.380035] EDAC DEBUG: edac_mc_dump_csrow:   csrow->nr_channels = 3
[ 1011.380037] EDAC DEBUG: edac_mc_dump_csrow:   csrow->channels = ffff8801149c2840
[ 1011.380039] EDAC DEBUG: edac_mc_dump_csrow:   csrow->mci = ffff880117426000
[ 1011.380041] EDAC DEBUG: edac_mc_dump_channel:   channel->chan_idx = 0
[ 1011.380042] EDAC DEBUG: edac_mc_dump_channel:     channel = ffff8801149c2860
[ 1011.380044] EDAC DEBUG: edac_mc_dump_channel:     channel->csrow = ffff8801169be000
[ 1011.380046] EDAC DEBUG: edac_mc_dump_channel:     channel->dimm = ffff88010fe90400
...
[ 1011.380095] EDAC DEBUG: edac_mc_dump_dimm: dimm0: channel 0 slot 0 mapped as virtual row 0, chan 0
[ 1011.380097] EDAC DEBUG: edac_mc_dump_dimm:   dimm = ffff88010fe90400
[ 1011.380099] EDAC DEBUG: edac_mc_dump_dimm:   dimm->label = 'CPU#0Channel#0_DIMM#0'
[ 1011.380101] EDAC DEBUG: edac_mc_dump_dimm:   dimm->nr_pages = 0x40000
[ 1011.380103] EDAC DEBUG: edac_mc_dump_dimm:   dimm->grain = 8
[ 1011.380104] EDAC DEBUG: edac_mc_dump_dimm:   dimm->nr_pages = 0x40000
...

(a rank-based memory controller would print, instead of "dimm?", "rank?"
 on the above debug info)

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>