Release msp430elf boards package for extended FRAM

[rei-vilo]

For MSP430 with Flash or FRAM > 48 kB, release new msp430elf boards package along existing msp430 boards package.

• Existing msp430 boards package would use GCC 4.6.6 and target

MSP-EXP430FR2433LP.build.extra_flags=-msmall -mcode-region=lower
MSP-EXP430FR4133LP.build.extra_flags=-msmall -mcode-region=lower
MSP-EXP430FR5739LP.build.extra_flags=-msmall -mcode-region=lower -mhwmult=f5series
MSP-EXP430FR2355LP.build.extra_flags=-msmall -mcode-region=lower
MSP-EXP430FR2311LP.build.extra_flags=-msmall -mcode-region=lower
MSP-EXP430G2231LP.build.extra_flags=
MSP-EXP430G2452LP.build.extra_flags=
MSP-EXP430G2553LP.build.extra_flags=
MSP-EXP430G2955SB.build.extra_flags=

• New msp430elf boards package would use GCC 7.3.1.24 and address

MSP-EXP430F5529LP.upload.maximum_size=48128 — should be 131072
MSP-EXP430FR5969LP.upload.maximum_size=48128 — should be 65536
MSP-EXP430FR5994LP.upload.maximum_size=262144
MSP-EXP430FR6989LP.upload.maximum_size=48128 — should be 131072

The new msp430elf boards package could be the now removed msp430-ng-core.