sys: ignore ineffective bitwise and from clang-tidy

When running clang-tidy, an 'ineffective bitwise and operation' (type
misc-redundant-expression) was detected on Z_CBPRINTF_IS_PCHAR macro.

As this behavior is expected, we are adding comment to ignore this macro
for the specific misc-redundant-expression check of clang-tidy

Signed-off-by: Nathan Olff <nathan@kickmaker.net>