[SERIAL] mark several serial tables const

This patch marks a few serial data structures const, moving them to
.rodata where they won't false-share cachelines with things that get
written to.

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/serial/8250_pci.c b/drivers/serial/8250_pci.c
index 5c3c039..8d92adf 100644
--- a/drivers/serial/8250_pci.c
+++ b/drivers/serial/8250_pci.c
@@ -468,7 +468,7 @@
 	0x9167, 0x9168, 0xA066, 0xA167, 0xA168, 0
 };
 
-static struct timedia_struct {
+static const struct timedia_struct {
 	int num;
 	unsigned short *ids;
 } timedia_data[] = {