checkpatch.pl: adjust typedef definition to QEMU coding style

Most QEMU typedefs are camelcase, starting with one uppercase letter
and containing at least one lowercase letter.  There are a few
all-uppercase types, add the most common too.

This fixes recognition of types in lines such as

    static __attribute__((unused)) inline void tcg_out8(TCGContext *s, uint8_t v)

(Example provided by Peter Maydell).

Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
