arm/arm: generating assemble code in ARM states by default

The following changes omit the arm version:

| commit d321080351
| Author: chao an <anchao@xiaomi.com>
| Date:   Fri Dec 2 02:52:18 2022 +0800
|
|     arm/cortex-[a|r]: generating assemble code in ARM states by default
|
|     Signed-off-by: chao an <anchao@xiaomi.com>

Signed-off-by: chao an <anchao@xiaomi.com>

arch/arm/src/arm/arm_cache.S

@@ -37,6 +37,8 @@
  ****************************************************************************/
 
 	.text
+	.syntax	unified
+	.arm
 
 /* Control functions caches and the write buffer c7
  * Register c7 controls the caches and the write buffer. The function of each cache

arch/arm/src/arm/arm_head.S

@@ -216,6 +216,8 @@
  */
 
 	.text
+	.syntax	unified
+	.arm
 	.global	__start
 	.type	__start, #function
 

arch/arm/src/arm/arm_nommuhead.S

@@ -52,6 +52,8 @@
  * below.
  */
 	.text
+	.syntax	unified
+	.arm
 	.global __start
 	.type	__start, #function
 __start:

arch/arm/src/arm/arm_vectoraddrexcptn.S

@@ -46,12 +46,8 @@
  ****************************************************************************/
 
 	.text
-
-/****************************************************************************
- * Public Functions
- ****************************************************************************/
-
-	.text
+	.syntax	unified
+	.arm
 
 /****************************************************************************
  *  Name: arm_vectoraddrexcptn

arch/arm/src/arm/arm_vectors.S

@@ -106,6 +106,8 @@
  ****************************************************************************/
 
 	.text
+	.syntax	unified
+	.arm
 
 /****************************************************************************
  * Public Functions

arch/arm/src/arm/arm_vectortab.S

@@ -34,6 +34,9 @@
  * Public Symbols
  ****************************************************************************/
 
+	.syntax	unified
+	.arm
+
 	.globl	_vector_start
 	.globl	_vector_end