netport_con.c: fix build errors and warnings

Fix build broken by accaa24c:

  CC      drivers/video/console/newport_con.o
drivers/video/console/newport_con.c: In function 'newport_show_logo':
drivers/video/console/newport_con.c:111: error: assignment of read-only location
drivers/video/console/newport_con.c:111: warning: assignment makes integer from pointer without a cast
drivers/video/console/newport_con.c:112: error: assignment of read-only location
drivers/video/console/newport_con.c:112: warning: assignment makes integer from pointer without a cast

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>