ipq40xx: ZTE MF287 fix sysupgrade

While refactoring support for the MF287 series, an entry in platform.sh
was overlooked - this fixes sysupgrade on this devices.

Signed-off-by: Andreas Böhler <[email protected]>

target/linux/ipq40xx/base-files/lib/upgrade/platform.sh

@@ -215,6 +215,7 @@ platform_do_upgrade() {
 	teltonika,rutx50 |\
 	zte,mf18a |\
 	zte,mf286d |\
+	zte,mf287 |\
 	zte,mf287plus |\
 	zte,mf287pro |\
 	zte,mf289f)