boot/at91bootstrap3: enable for cortexa7

Enable this bootloader for cortex a7 based SoCs: support for the
sama7g5 SoC is now in upstream at91bootstrap3, and it is a Cortex-A7
based SoC.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 33003a47c505ba38b58f7f58c34b7a7c50879b24)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

boot/at91bootstrap3/Config.in

@@ -1,6 +1,6 @@
 config BR2_TARGET_AT91BOOTSTRAP3
 	bool "AT91 Bootstrap 3"
-	depends on BR2_arm926t || BR2_cortex_a5
+	depends on BR2_arm926t || BR2_cortex_a5 || BR2_cortex_a7
 	help
 	  AT91Bootstrap is a first level bootloader for the Atmel AT91
 	  devices. It integrates algorithms for: