toolchain/gcc: switch to version 11 by default

gcc10 seem to increase build size and gcc11 seem to fix that.

Compile tests:
* all

Runtime tests:
* ath79
* mpx85xx/p2020
* mvebu
* x86/64

Special thanks to Rosen for fixing layerscape & bcm63xx

Signed-off-by: Paul Spooren <mail@aparcar.org>
Reviewed-by: Rui Salvaterra <rsalvaterra@gmail.com>
Acked-by: Rosen Penev <rosenp@gmail.com>
Acked-by: Rui Salvaterra <rsalvaterra@gmail.com>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Stijn Tintel <stijn@linux-ipv6.be>
Acked-by: Aleksander Jan Bajkowski <A.Bajkowski@stud.elka.pw.edu.pl>
Tested-by: Pawel Dembicki <paweldembicki@gmail.com>
Tested-by: Aleksander Jan Bajkowski <A.Bajkowski@stud.elka.pw.edu.pl>

toolchain/gcc/Config.in

@@ -2,7 +2,7 @@
 
 choice
 	prompt "GCC compiler Version" if TOOLCHAINOPTS
-	default GCC_USE_VERSION_10
+	default GCC_USE_VERSION_11
 	help
 	  Select the version of gcc you wish to use.
 

toolchain/gcc/Config.version

@@ -2,12 +2,12 @@ config GCC_VERSION_8
 	default y if GCC_USE_VERSION_8
 	bool
 
-config GCC_VERSION_11
-	default y if GCC_USE_VERSION_11
+config GCC_VERSION_10
+	default y if GCC_USE_VERSION_10
 	bool
 
 config GCC_VERSION
 	string
 	default "8.4.0"		if GCC_VERSION_8
-	default "11.2.0"	if GCC_VERSION_11
-	default "10.3.0"
+	default "10.3.0"	if GCC_VERSION_10
+	default "11.2.0"