Misc changes to README files; Update SAMA5D3x-EK NxWM configuration to use Calibration instruction messages

SAMA5 LCDC:  Correct how framebuffer memory was being mapped; Remove options to get framebuffer memory in various.  Because of the mapping and aligment requirements, those options really cannot be supported

SAMA5 LCDC:  Wait when the LCDC is resynchronizing (SIF); Try start-up parameters from Barebox (this still don't work)

SAMA5 LCDC: Default resolution if now RGB565; Add option to select a different output resolution than the sofware resolution (needs to the 24BPP for this LCD).

SAMA5 LCDC: Move DMA descriptors out of internal SRAM and into SDRAM. I am not completely clear, but it looks like the LCDC cannot support DMA from internal SRAM

Add framework for Spark Core board support.  The initial commit is a clone of the Maple Mini and still needs Spark customizations

Add freedom-kl25z/minnsh configuration:  This is an experiment to see just how small we and get an NSH configuration.  From Alan Carvalho de Assis.

KL25Z:  Add low-level up_lowgetc function that can be used to provide an NSH console when the file system (and hence the serial driver) is disabled.  From Alan Carvalho de Assis

KL25Z:  Add low-level up_lowgetc function that can be used to provide an NSH console when the file system (and hence the serial driver) is disabled.  From Alan Carvalho de Assis