cstyle: ignore old non-POSIX types in macro invocations

In code generation macros, we often use names like uint when
constructing handler functions. These are not being used as types, so
exclude them from the admonishment to use POSIX type names.

Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes #16840