meta-ampere: mtjade: Fix SCP failover handling

"BMC_I2C_BACKUP_SEL" was not defined anywhere, so script
"ampere_scp_failover.sh" fails to execute and SCP can't
switch to the secondary EEPROM to boot in case of failed
primary EEPROM firmware.

This commit defines BMC_I2C_BACKUP_SEL to 8 in "gpio-defs.sh"
, which is gpio B0

Tested:

1. BMC on, Host on, flash good SCP firmware to secondary EEPROM,
flash bad SCP firmware to primary EEPROM that simulate SCP
authentication failure
	=> Host boots OK with secondary EEPROM
   Check gpio BMC_I2C_BACKUP_SEL
	=> it will be set to 0

Signed-off-by: chaul.ampere <chaul@amperecomputing.com>
Change-Id: Ibb891042deb051f8100f9a88dd3619bce12c181f
diff --git a/meta-ampere/meta-jade/recipes-ampere/platform/ampere-utils/gpio-defs.sh b/meta-ampere/meta-jade/recipes-ampere/platform/ampere-utils/gpio-defs.sh
index fc0edd6..e0a7c02 100644
--- a/meta-ampere/meta-jade/recipes-ampere/platform/ampere-utils/gpio-defs.sh
+++ b/meta-ampere/meta-jade/recipes-ampere/platform/ampere-utils/gpio-defs.sh
@@ -18,6 +18,7 @@
 
 
 ### Table 1: GPIO Assignments
+BMC_I2C_BACKUP_SEL=8
 S0_CPU_FW_BOOT_OK=48
 CPU_BMC_OVERTEMP_L=51
 CPU_BMC_HIGHTEMP_L=72