MAINTAINERS: Update entry for EDAC-SKYLAKE

Code refactoring to share some source code with a new EDAC driver
resulted in renaming one file (skx_edac.c became skx_base.c) and adding
a new file (skx_common.c).

Update the file pattern in MAINTAINERS to take account of this change.

Fixes: 98f2fc82 ("EDAC, skx_edac: Delete duplicated code")
Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Aristeu Rozanski <aris@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: https://lkml.kernel.org/r/20190325232932.GA8869@agluck-desk