be2net: make two arrays static const, makes object smaller

Don't populate the arrays on the stack but instead make them
static const. Makes the object code smaller by 281 bytes.

Before:
   text	   data	    bss	    dec	    hex	filename
  87553	   5672	      0	  93225	  16c29	benet/be_cmds.o

After:
   text	   data	    bss	    dec	    hex	filename
  87112	   5832	      0	  92944	  16b10	benet/be_cmds.o

(gcc version 9.2.1, amd64)

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>