edac: Don't initialize csrow's first_page & friends when not needed

edac: Don't initialize csrow's first_page & friends when not needed

Almost all edac	drivers	initialize csrow_info->first_page,
csrow_info->last_page and csrow_info->page_mask. Those vars are
used inside the EDAC core, in order to calculate the csrow affected
by an error, by using the routine edac_mc_find_csrow_by_page().

However, very few drivers actually use it:
        e752x_edac.c
        e7xxx_edac.c
        i3000_edac.c
        i82443bxgx_edac.c
        i82860_edac.c
        i82875p_edac.c
        i82975x_edac.c
        r82600_edac.c

There also a few other drivers that have their own calculus
formula internally using those vars.

All the others are just wasting time by initializing those
data.

While initializing data without using them won't cause any troubles, as
those information is stored at the wrong place (at csrows structure), it
is better to remove what is unused, in order to simplify the next patch.

Reviewed-by: Aristeu Rozanski <[email protected]>
Acked-by: Borislav Petkov <[email protected]>
Acked-by: Chris Metcalf <[email protected]>
Cc: Doug Thompson <[email protected]>
Cc: Hitoshi Mitake <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: "Niklas Söderlund" <[email protected]>
Cc: Josh Boyer <[email protected]>
Cc: Jiri Kosina <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>