Mark sal_Char, sal_sChar, sal_uChar as deprecated

...there never was a good reason to have SAL abstractions for the C/C++ char types anyway.

Change-Id: Id5da718cf26f12ebe57bc71e076c32d763c0982e
Unwind occurrences of deprecated sal_sChar, sal_uChar

Change-Id: I76be464200d486efef9c8a7e957c310c9adae3b8