[Buildroot] [git commit branch/2021.08.x] configs/qemu_aarch64_sbsa_defconfig: use ARM cortex a57

[Peter Korsgaard]

commit: https://git.buildroot.net/buildroot/commit/?id=b6d9a84b2ffcc443a600b42d06253ed244a002aa
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2021.08.x

Cortex-a53 is not a vaild CPU supported by the SBSA reference machine
[0], so qemu fails to boot in our current defconfig:

  qemu-system-aarch64: sbsa-ref: CPU type other than the built-in cortex-a57 not supported

Use ARM cortex-a57 which is the CPU that SBSA was meant to emulate [1]

[0] https://git.qemu.org/?p=qemu.git;a=commitdiff;h=4f335a6381f83beb5d6ac0d3993514379454a99d
[1] https://git.qemu.org/?p=qemu.git;a=commitdiff;h=64580903c2b3aee08d74d64e6248a313b246cb69

Signed-off-by: Romain Naour <romain.naour at gmail.com>
Cc: Dick Olsson <hi at senzilla.io>
Reviewed-by: Dick Olsson <hi at senzilla.io>
[yann.morin.1998 at free.fr: update the commit log with info from Dick]
Signed-off-by: Yann E. MORIN <yann.morin.1998 at free.fr>
(cherry picked from commit 17c516d67afd041093964824dcb0dfa8fc618fe6)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
 board/qemu/aarch64-sbsa/readme.txt  | 2 +-
 configs/qemu_aarch64_sbsa_defconfig | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/board/qemu/aarch64-sbsa/readme.txt b/board/qemu/aarch64-sbsa/readme.txt
index 7935108ef1..b62947f55f 100644
--- a/board/qemu/aarch64-sbsa/readme.txt
+++ b/board/qemu/aarch64-sbsa/readme.txt
@@ -17,7 +17,7 @@ Run the emulation with:
 
   qemu-system-aarch64 \
     -M sbsa-ref \
-    -cpu cortex-a53 \
+    -cpu cortex-a57 \
     -smp 4 \
     -m 1024 \
     -nographic \
diff --git a/configs/qemu_aarch64_sbsa_defconfig b/configs/qemu_aarch64_sbsa_defconfig
index d014140bf5..9285ad7586 100644
--- a/configs/qemu_aarch64_sbsa_defconfig
+++ b/configs/qemu_aarch64_sbsa_defconfig
@@ -1,6 +1,6 @@
 # Architecture
 BR2_aarch64=y
-BR2_cortex_a53=y
+BR2_cortex_a57=y
 
 # Toolchain
 BR2_TOOLCHAIN_BUILDROOT_WCHAR=y