drivers/intel/fsp2_0: Disable display of FSP header

Add a Kconfig value to enable display of FSP header.  Move the display
code into a separate module to remove it entirely from the final image.

TEST=Build and run on Galileo Gen2

Change-Id: I7047a9e58e6a6481c8453dbfebfbfe69dc8823d8
Signed-off-by: Lee Leahy <leroy.p.leahy@intel.com>
Reviewed-on: https://review.coreboot.org/16002
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
6 files changed