treewide: sysupgrade: get rid of platform_nand_pre_upgrade()

1) nand_do_upgrade() is always called by a target code
2) nand_do_upgrade() starts with calling platform_nand_pre_upgrade()

It means there is no need for the platform_nand_pre_upgrade() callback
at all. All code that was present there could bo moved & simplly called
by a target right before the nand_do_upgrade().

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

target/linux/ramips/base-files/lib/upgrade/platform.sh

@@ -9,17 +9,6 @@ platform_check_image() {
 	return 0
 }
 
-platform_nand_pre_upgrade() {
-	local board=$(board_name)
-
-	case "$board" in
-	ubiquiti,edgerouterx|\
-	ubiquiti,edgerouterx-sfp)
-		platform_upgrade_ubnt_erx "$1"
-		;;
-	esac
-}
-
 platform_do_upgrade() {
 	local board=$(board_name)
 
@@ -35,8 +24,6 @@ platform_do_upgrade() {
 	hiwifi,hc5962|\
 	netgear,r6220|\
 	netgear,r6350|\
-	ubiquiti,edgerouterx|\
-	ubiquiti,edgerouterx-sfp|\
 	xiaomi,mir3g|\
 	xiaomi,mir3p)
 		nand_do_upgrade "$1"
@@ -45,6 +32,10 @@ platform_do_upgrade() {
 		MTD_ARGS="-t romfile"
 		default_do_upgrade "$1"
 		;;
+	ubiquiti,edgerouterx|\
+	ubiquiti,edgerouterx-sfp)
+		platform_upgrade_ubnt_erx "$1"
+		;;
 	*)
 		default_do_upgrade "$1"
 		;;

target/linux/ramips/base-files/lib/upgrade/ubnt.sh

@@ -73,4 +73,6 @@ platform_upgrade_ubnt_erx() {
 	fi
 
 	ubnt_update_target_kernel ${factory_mtd} ${kernel_part} || exit 1
+
+	nand_do_upgrade "$1"
 }