t-msp430 (MULTILIB_OPTIONS): Add multilibs for the different types of hardware multiply available on the MSP430.
* config/msp430/t-msp430 (MULTILIB_OPTIONS): Add multilibs for the
different types of hardware multiply available on the MSP430.
(MULTILIB_DIRNAMES): Likewise.
(MULTILIB_EXCEPTIONS): Add exceptions for incompatible cpus and
hardware multiply types.
(MULTILIB_MATCHES): Add matches for known MCU names and hardware
multiply types.