at91: add kernel support for sama7g5 soc

Add kernel support for SAMA7G5 by back-porting mainline kernel patches.
Among SAMA7G5 features could be remembered:
- ARM Cortex-A7
- double data rate multi-port dynamic RAM controller supporting DDR2,
  DDR3, DDR3L, LPDDR2, LPDDR3 up to 533MHz
- peripherals for audio, video processing
- 1 gigabit + 1 megabit Ethernet controllers
- 6 CAN controllers
- trust zone support
- DVFS for CPU
- criptography IPs

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>

target/linux/at91/patches-5.10/99-scripts-fix-compilation-error.patch

@@ -0,0 +1,26 @@
+From 6d18eaaaff92f928eab6fad2708b6d28785b4872 Mon Sep 17 00:00:00 2001
+From: Claudiu Beznea <claudiu.beznea@microchip.com>
+Date: Wed, 13 Oct 2021 08:32:07 +0300
+Subject: [PATCH] scripts: fix compilation error
+
+Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
+---
+ scripts/Makefile | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/scripts/Makefile b/scripts/Makefile
+index 9adb6d247818..035c1fe113ad 100644
+--- a/scripts/Makefile
++++ b/scripts/Makefile
+@@ -21,7 +21,7 @@ HOSTCFLAGS_asn1_compiler.o = -I$(srctree)/include
+ HOSTCFLAGS_sign-file.o = $(CRYPTO_CFLAGS)
+ HOSTLDLIBS_sign-file = $(CRYPTO_LIBS)
+ HOSTCFLAGS_extract-cert.o = $(CRYPTO_CFLAGS)
+-HOSTLDLIBS_extract-cert = $(CRYPTO_LIBS)
++HOSTLDLIBS_extract-cert = $(CRYPTO_LIBS) -lpthread
+ 
+ ifdef CONFIG_UNWINDER_ORC
+ ifeq ($(ARCH),x86_64)
+-- 
+2.25.1
+