libvpd: New logger macro is introduced
libvpd: New logger macro is introduced

log_msg is a macro which takes priority, logging message as params and logs
messages. It supports variable arguments, so that it can be used with any
number of params.
log_<X> macro is a specific macro, who calls log_msg with priority as a param.
log_<X> macro is able keep macro name as understable with error priority and
can be undefined for any specific priority error.

Signed-off-by: Ankit Kumar <7d7f3b0de32b6cc2e9608ebf7986c26b5954d288@linux.vnet.ibm.com>
[Minor fix to logger output - Vasant]
Signed-off-by: Vasant Hegde <a6d753843573f7bfed5075c1e875b0be8007a0ab@linux.vnet.ibm.com>

kamalesh-babulal/libvpd,kamalesh-babulal/libvpd,kamalesh-babulal/libvpd