OMAP3: Use functions print_cpuinfo() and checkboard()

Use the functions print_cpuinfo() and checkboard() to
display the cpu and board specific information.

These functions reuse content from the existing function
display_board_info() - which has been removed.

Also, updated the existig OMAP3 configurations to
define:
 - CONFIG_DISPLAY_CPUINFO
 - CONFIG_DISPLAY_BOARDINFO

Signed-off-by: Sanjeev Premi <premi@ti.com>