arch: arm: userspace: minor refactor in z_arch_is_user_context

Refactor z_arch_is_user_context() for ARM, so it uses
the CMSIS CONTROL_nPRIV_Msk instead of hard-coded 0x1.
Fixing also some typos in include/arch/arm/syscall.h.

Signed-off-by: Ioannis Glaropoulos <[email protected]>

Author: ioannisg

include/arch/arm/syscall.h

@@ -6,9 +6,9 @@
 
 /**
  * @file
- * @brief ARM specific sycall header
+ * @brief ARM specific syscall header
  *
- * This header contains the ARM specific sycall interface.  It is
+ * This header contains the ARM specific syscall interface.  It is
  * included by the syscall interface architecture-abstraction header
  * (include/arch/syscall.h)
  */
@@ -26,6 +26,7 @@
 
 #include <zephyr/types.h>
 #include <stdbool.h>
+#include <arch/arm/cortex_m/cmsis.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -167,7 +168,7 @@ static inline bool z_arch_is_user_context(void)
 
 	/* if not handler mode, return mode information */
 	__asm__ volatile("mrs %0, CONTROL\n\t" : "=r"(value));
-	return (value & 0x1) ? true : false;
+	return (value & CONTROL_nPRIV_Msk) ? true : false;
 }
 
 #ifdef __cplusplus