ck_pr/arm: Don't use ldrexd/strexd if we're building for armv6.

include/gcc/arm/ck_f_pr.h

@@ -91,7 +91,9 @@
 #define CK_F_PR_INC_UINT
 #define CK_F_PR_LOAD_16
 #define CK_F_PR_LOAD_32
+#if defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__)
 #define CK_F_PR_LOAD_64
+#endif
 #define CK_F_PR_LOAD_8
 #define CK_F_PR_LOAD_CHAR
 #define CK_F_PR_LOAD_INT
@@ -125,7 +127,9 @@
 #define CK_F_PR_STALL
 #define CK_F_PR_STORE_16
 #define CK_F_PR_STORE_32
+#if defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__)
 #define CK_F_PR_STORE_64
+#endif
 #define CK_F_PR_STORE_8
 #define CK_F_PR_STORE_CHAR
 #define CK_F_PR_STORE_INT

include/gcc/arm/ck_pr.h

@@ -131,6 +131,8 @@ CK_PR_LOAD_S(char, char, "ldrb")
 #undef CK_PR_LOAD_S
 #undef CK_PR_LOAD
 
+#if defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__)
+
 CK_CC_INLINE static uint64_t
 ck_pr_md_load_64(const uint64_t *target)
 {
@@ -143,6 +145,8 @@ ck_pr_md_load_64(const uint64_t *target)
 	return (ret);
 }
 
+#endif
+
 #define CK_PR_STORE(S, M, T, C, I)				\
 	CK_CC_INLINE static void				\
 	ck_pr_md_store_##S(M *target, T v)			\
@@ -170,6 +174,8 @@ CK_PR_STORE_S(char, char, "strb")
 #undef CK_PR_STORE_S
 #undef CK_PR_STORE
 
+#if defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__)
+
 CK_CC_INLINE static void
 ck_pr_md_store_64(const uint64_t *target, uint64_t value)
 {
@@ -186,6 +192,8 @@ ck_pr_md_store_64(const uint64_t *target, uint64_t value)
 				: "memory", "cc");
 }
 
+#endif
+
 CK_CC_INLINE static bool
 ck_pr_cas_64_value(uint64_t *target, uint64_t compare, uint64_t set, uint64_t *value)
 {