style: put the repository assembly in gasm fmt canonical form

Assisted-by: GLM 5.3 Flash

testdata/verify/loadstore_riscv64.s

@@ -4,14 +4,14 @@
 #include "textflag.h"
 
 TEXT ·ldst(SB), NOSPLIT, $0
-	LD (X8), X9
-	SD X9, (X8)
-	LW (X8), X9
-	SW X9, (X8)
-	LD 8(X2), X10
-	SD X10, 16(X2)
-	LW 4(X2), X11
-	SW X11, 8(X2)
+	LD  (X8), X9
+	SD  X9, (X8)
+	LW  (X8), X9
+	SW  X9, (X8)
+	LD  8(X2), X10
+	SD  X10, 16(X2)
+	LW  4(X2), X11
+	SW  X11, 8(X2)
 	RET
 
 TEXT ·addi4spn(SB), NOSPLIT, $0