Dir 4.6 and usage of "fast" types in stdint.h

[misra-c]

The use of types such as int_fast8_t and int_least8_t violates Directive 4.6.

The amplification to directive 4.6 states:

A type must not be defined with a specific length unless the implemented type is actually of that length.

The use of types such as int_fast8_t and int_least8_t does not guarantee that the type is actually of 8-bits.