[media] e4000: fix compiler warning

drivers/media/tuners/e4000.c:287:3: warning: this decimal constant is unsigned only in ISO C90
   .rangehigh  =  2208000000L,
   ^

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>