media: tuners: mxl5005s: make arrays static const, reduces object code size

Don't populate the arrays RegAddr on the stack, instead make them static
const.  Makes the object code smaller by over 980 bytes:

Before:
   text	   data	    bss	    dec	    hex	filename
  64923	    304	      0	  65227	   fecb	drivers/media/tuners/mxl5005s.o

After:
   text	   data	    bss	    dec	    hex	filename
  63779	    464	      0	  64243	   faf3	drivers/media/tuners/mxl5005s.o

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>