gdb: Backport patch to changes with AVX and MPX

The current MPX target descriptions assume that MPX is always combined
with AVX, however that's not correct.  We can have machines with MPX
and without AVX; or machines with AVX and without MPX.

This patch adds new target descriptions for machines that support
both MPX and AVX, as duplicates of the existing MPX descriptions.

The following commit will remove AVX from the MPX-only descriptions.

This commit is backported from 7.12

(From OE-Core rev: 059d459d48bd42a282005698c4dc4a3ecbd2d88f)

Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/gdb/gdb-7.9.1.inc

@@ -7,3 +7,4 @@ LIC_FILES_CHKSUM = "file://COPYING;md5=59530bdf33659b29e73d4adb9f9f6552 \
 SRC_URI[md5sum] = "f3b97de919a9dba84490b2e076ec4cb0"
 SRC_URI[sha256sum] = "4994ad986726ac4128a6f1bd8020cd672e9a92aa76b80736563ef992992764ef"
 
+SRC_URI += "file://0001-7.9.1-Add-target-descriptions-for-AVX-MPX.patch"