[console] Add LOG_ALL as a synonym for LOG_DEBUG

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/syslog.h

 /** Do not log any messages */
 #define LOG_NONE -1
 
+/** Log all messages */
+#define LOG_ALL LOG_DEBUG
+
 extern void log_vprintf ( const char *fmt, va_list args );
 
 extern void __attribute__ (( format ( printf, 1, 2 ) ))