ARM: da850evm: Enable USE_TINY_PRINTF

The SPL space is limited.  In order to try to enable DM in SPL,
we need more space. This reduces the size of SPL by ~2.7K

before:
   text	   data	    bss	    dec	    hex	filename
  20760	   1216	     80	  22056	   5628	spl/u-boot-spl
after:
   text	   data	    bss	    dec	    hex	filename
  17947	   1216	     80	  19243	   4b2b	spl/u-boot-spl

Signed-off-by: Adam Ford <aford173@gmail.com>