checkpatch: fix wildcard DT compatible string checking

We attempt to search for compatible strings which use a variable token in
the documented name such as <chip> or <soc>.  While this was attempted to
be handled, it's utterly broken.

The desired forms of matching are:

vendor,<chip>-*
vendor,name<part#>-*

For <chip>, lower case characters and numbers are permitted.  For <part#>,
only numeric values are allowed.

With this change, the number of missing compatible strings reported in
arch/arm/boot/dts is reduced from 1071 to 960.

Reported-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Florian Vaussard <florian.vaussard@epfl.ch>
Cc: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>