x64: extract cfi macros into a new file

arch/x64/cfi.s

+# macros for cfi annotations
+
+.macro pushq_cfi reg
+	pushq \reg
+	.cfi_adjust_cfa_offset 8
+	.cfi_rel_offset \reg, 0
+.endm
+
+.macro popq_cfi reg
+	popq \reg
+	.cfi_adjust_cfa_offset -8
+	.cfi_restore \reg
+.endm
+

arch/x64/entry.s

 
-.macro pushq_cfi reg
-	pushq \reg
-	.cfi_adjust_cfa_offset 8
-	.cfi_rel_offset \reg, 0
-.endm
-
-.macro popq_cfi reg
-	popq \reg
-	.cfi_adjust_cfa_offset -8
-	.cfi_restore \reg
-.endm
+.include "arch/x64/cfi.s"
 
 .macro exception_entry name, handler, has_error_code
 	.global \name