reel_board: Do not include Bluetooth to every project
reel_board: Do not include Bluetooth to every project

Including Bluetooth to every project unnecessary increase size of the
project, for example hello world sizes:

Memory region         Used Size  Region Size  %age Used
           FLASH:       48492 B         1 MB      4.62%
            SRAM:       11236 B       256 KB      4.29%
        IDT_LIST:         136 B         2 KB      6.64%

after the patch:

Memory region         Used Size  Region Size  %age Used
           FLASH:       13344 B         1 MB      1.27%
            SRAM:        4004 B       256 KB      1.53%
        IDT_LIST:          72 B         2 KB      3.52%

3+ times difference.
PS: It also crashes when 802.15.4 enabled.

Signed-off-by: Andrei Emeltchenko <a6565233ddc88e4fb9c66c1d70743223493f2ed4@intel.com>

zephyrproject-rtos/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,nashif/zephyr,ldts/zephyr,galak/zephyr,punitvara/zephyr,Vudentz/zephyr,Vudentz/zephyr,nashif/zephyr,Vudentz/zephyr,finikorg/zephyr,punitvara/zephyr,explora26/zephyr,explora26/zephyr,ldts/zephyr,finikorg/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,explora26/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,finikorg/zephyr,galak/zephyr,nashif/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,punitvara/zephyr,Vudentz/zephyr,explora26/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,finikorg/zephyr,punitvara/zephyr,zephyrproject-rtos/zephyr,punitvara/zephyr,galak/zephyr,Vudentz/zephyr