Constify struct cpu_device_id instances

There is currently no case where a struct cpu_device_id instance needs
to be modified. Thus, declare all instances as const.

Change-Id: I5ec7460b56d75d255b3451d76a46df76a51d6365
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-on: https://review.coreboot.org/22526
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/cpu/via/c3/c3_init.c

@@ -35,7 +35,7 @@ static struct device_operations cpu_dev_ops = {
 	.init     = c3_init,
 };
 
-static struct cpu_device_id cpu_table[] = {
+static const struct cpu_device_id cpu_table[] = {
 	{ X86_VENDOR_CENTAUR, 0x0670 },		// VIA C3 Samual 2 + Ezra
 	{ X86_VENDOR_CENTAUR, 0x0680 },		// VIA C3 Ezra-T
 	{ X86_VENDOR_CENTAUR, 0x0690 },		// VIA C3 Nehemiah

src/cpu/via/c7/c7_init.c

@@ -213,7 +213,7 @@ static struct device_operations cpu_dev_ops = {
  * allows us to keep the table significantly smaller.
  */
 
-static struct cpu_device_id cpu_table[] = {
+static const struct cpu_device_id cpu_table[] = {
 	{X86_VENDOR_CENTAUR, 0x06A0},	// VIA C7 Esther
 	{X86_VENDOR_CENTAUR, 0x06A9},	// VIA C7 Esther
 	{X86_VENDOR_CENTAUR, 0x06D0},	// VIA C7-M

src/cpu/via/nano/nano_init.c

@@ -188,7 +188,7 @@ static struct device_operations cpu_dev_ops = {
 	.init = nano_init,
 };
 
-static struct cpu_device_id cpu_table[] = {
+static const struct cpu_device_id cpu_table[] = {
 	{X86_VENDOR_CENTAUR, 0x06f2},	// VIA NANO 1000/2000 Series
 	{X86_VENDOR_CENTAUR, 0x06f8},	// VIA NANO 3000 rev B0
 	{X86_VENDOR_CENTAUR, 0x06fa},	// VIA NANO 3000 rev B2