CC2538: Add CONF parameters to select boot loader backdoor pin and logic level.
Rename FLASH_CCA_CONF_BOOTLDR_BACKDOOR_PIN to FLASH_CCA_CONF_BOOTLDR_BACKDOOR_PORT_A_PIN.
Un-indent preprocessor directives.
Changes suggested by @bthebaudeau.
CC2538: Add WATCHDOG_CONF_ENABLE to optionally disable the watchdog timer.
CC2538: Add FLASH_CONF_ORIGIN and FLASH_CONF_SIZE config parameters.
Merge pull request #665 from hexluthor/cc2538-flash-conf

CC2538: Add FLASH_CONF_ORIGIN and FLASH_CONF_SIZE config parameters.
Merge pull request #641 from hexluthor/backdoor-conf

CC2538: Add CONF parameters to select boot loader backdoor pin and logic level
Merge pull request #661 from hexluthor/watchdog-enable

CC2538: Add WATCHDOG_CONF_ENABLE to optionally disable the watchdog timer
Added flags to enable 20-bit support from msp430-gcc 4.7.x