Don't populate the array degrees on the stack but instead make it
static const. Makes the object code smaller by 46 bytes.

Before:
   text	   data	    bss	    dec	    hex	filename
   5356	   1560	      0	   6916	   1b04	dw_mmc-hi3798cv200.o

After:
   text	   data	    bss	    dec	    hex	filename
   5214	   1656	      0	   6870	   1ad6	dw_mmc-hi3798cv200.o

(gcc version 9.2.1, amd64)
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>