llext: Include aarch64 in LLEXT sample

Add entries in sample to test aarch64 architecture that supports
llext subsystem.

Signed-off-by: Adam Wojasinski <[email protected]>

Author: awojasinski

samples/subsys/llext/modules/sample.yaml

@@ -3,12 +3,14 @@ common:
   platform_allow:
     - qemu_cortex_a9          # ARM Cortex-A9 (ARMv7-A ISA)
     - qemu_cortex_r5          # ARM Cortex-R5 (ARMv7-R ISA)
+    - qemu_cortex_a53         # ARM Cortex-A53 (ARMv8-A ISA)
     - mps2/an385              # ARM Cortex-M3 (ARMv7-M ISA)
     - mps2/an521/cpu0         # ARM Cortex-M33 (ARMv8-M ISA)
     - qemu_xtensa
   integration_platforms:
     - qemu_xtensa
     - mps2/an385
+    - qemu_cortex_a53
   harness: console
 
 sample: