This commit eliminates the BOARDIOC_TSCTEST_SETUP command.

Squashed commit of the following:

    configs:  Each board now initializes the touchscreen controller as a normal part of its board bring-up.  board_tsc_setup() is gone; the touchscreen controller is now treated like any other on-board device.
    Remove all support for BOARDIOC_TSCTEST_SETUP
    Move prototype for board_tsc_setup() from include/nuttx/board.h to individual board header files.