net: 3c509: make the array if_names static const, makes object smaller

Don't populate the array if_names on the stack but instead it
static const. Makes the object code smaller by 99 bytes.

Before:
   text    data     bss     dec     hex filename
  27886   10752     672   39310    998e ./drivers/net/ethernet/3com/3c509.o

After:
   text    data     bss     dec     hex filename
  27723   10816     672   39211    992b ./drivers/net/ethernet/3com/3c509.o

(gcc version 10.2.0)

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210801152650.146572-1-colin.king@canonical.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>