soc: cc13x2_cc26x2: support setting CCFG values via Kconfig

Several customer configuration (CCFG) settings are useful for
development and deployment. This commit adds support for setting CCFG
values via Kconfig. It follows TI's recommendation of setting CCFG
values and then including the TI provided CCFG. This commit includes
support for enabling the ROM bootloader and additional settings can be
added as needed.

Signed-off-by: Brett Witherspoon <spoonb@cdspooner.com>