armv7-a/Toolchain.defs: Update LLVM arch type to thumbv7a

Changed the LLVM architecture type from thumbv7 to thumbv7a in
Toolchain.defs to better match the ARMv7-A architecture specification.

This change ensures proper code generation and optimization for
Cortex-A series processors when using the Thumb instruction set.

Signed-off-by: Huang Qi <[email protected]>

Author: no1wudi

arch/arm/src/armv7-a/Toolchain.defs

@@ -35,7 +35,7 @@ else ifeq ($(CONFIG_ARCH_CORTEXA9),y)
 endif
 
 ifeq ($(CONFIG_ARM_THUMB),y)
-  LLVM_ARCHTYPE := thumbv7
+  LLVM_ARCHTYPE := thumbv7a
 else
   LLVM_ARCHTYPE := armv7a
 endif