tty: frv, remove unused serial macros

STD_COM_FLAGS needs not be defined as it is not used anywhere on frv.

SERIAL_PORT_DFNS is defined to be empty. 8250 is aware of empty
SERIAL_PORT_DFNS and does:
 #ifndef SERIAL_PORT_DFNS
 #define SERIAL_PORT_DFNS
 #endif

So no need to define it on frv.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/frv/include/asm/serial.h

@@ -12,7 +12,3 @@
  * the base baud is derived from the clock speed and so is variable
  */
 #define BASE_BAUD 0
-
-#define STD_COM_FLAGS		UPF_BOOT_AUTOCONF
-
-#define SERIAL_PORT_DFNS