Use `grep -E` or plain `grep` instead of `egrep`

`egrep` has been deprecated in GNU grep since 2007,
and since 3.8 it emits obsolescence warnings:
https://git.savannah.gnu.org/cgit/grep.git/commit/?id=a9515624709865d480e3142fd959bccd1c9372d1
Acked-by: Dhruva Gole <d-gole@ti.com>

Makefile: add coccicheck target

Coccinelle is a program for static code analysis.
For details on Coccinelle see

http://coccinelle.lip6.fr/

Add scripts/coccicheck copied from Linux kernel v4.14.

The coccicheck script executes the tests *.cocci in
directory scripts/coccinelle by calling spatch.

In Makefile add a coccicheck target. You can use it with

make coccicheck MODE=<mode>

where mode in patch, report, context, org.

Add a copy of Linux v4.14 file Documentation/dev-tools/coccinelle.rst
as doc/README.coccinelle.

Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

Makefile: add coccicheck target

Coccinelle is a program for static code analysis.
For details on Coccinelle see

http://coccinelle.lip6.fr/

Add scripts/coccicheck copied from Linux kernel v4.14.

The coccicheck script executes the tests *.cocci in
directory scripts/coccinelle by calling spatch.

In Makefile add a coccicheck target. You can use it with

make coccicheck MODE=<mode>

where mode in patch, report, context, org.

Add a copy of Linux v4.14 file Documentation/dev-tools/coccinelle.rst
as doc/README.coccinelle.

Cc: Simon Glass <sjg@chromium.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>