checkpatch: improve ignoring CamelCase SI style variants like mA

Ignore all upper-case variants before and after SI units like mA, mV and
uV so uses like RANGE_mA do not emit a CAMELCASE message.

Link: http://lkml.kernel.org/r/5ce6f9131327fd2e12d7a0e20a55f588448de090.camel@perches.com


Signed-off-by: Joe Perches <joe@perches.com>
Cc: Jules Irenge <jbi.octave@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>