libc: Remove printf-like functions

They are too big for the Trusted Firmware, and it can be confusing to
have two versions of the same functions with different names. tf_printf
and tf_snprintf will replace them in the next patch.

Change-Id: I978414ac169cc3156e249549ef101a70eb31a295
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>