shared/runtime/gchelper_rv64i: Fix opcode sw/sd typo.

The version of the assembly code for the GC helper that was committed
ended up being a version that had an opcode typo in.

The code was tested and working, but an undo operation too many when
cleaning up the file before committing checked in the wrong version.

Signed-off-by: Alessandro Gatti <a.gatti@frob.it>

shared/runtime/gchelper_rv64i.s

@@ -31,18 +31,18 @@ gc_helper_get_regs_and_sp:
 
     /* Store registers into the given array. */
 
-    sw    x8,  0(x10)  /* Save S0.  */
-    sw    x9,  8(x10)  /* Save S1.  */
-    sw   x18, 16(x10)  /* Save S2.  */
-    sw   x19, 24(x10)  /* Save S3.  */
-    sw   x20, 32(x10)  /* Save S4.  */
-    sw   x21, 40(x10)  /* Save S5.  */
-    sw   x22, 48(x10)  /* Save S6.  */
-    sw   x23, 56(x10)  /* Save S7.  */
-    sw   x24, 64(x10)  /* Save S8.  */
-    sw   x25, 72(x10)  /* Save S9.  */
-    sw   x26, 80(x10)  /* Save S10. */
-    sw   x27, 88(x10)  /* Save S11. */
+    sd    x8,  0(x10)  /* Save S0.  */
+    sd    x9,  8(x10)  /* Save S1.  */
+    sd   x18, 16(x10)  /* Save S2.  */
+    sd   x19, 24(x10)  /* Save S3.  */
+    sd   x20, 32(x10)  /* Save S4.  */
+    sd   x21, 40(x10)  /* Save S5.  */
+    sd   x22, 48(x10)  /* Save S6.  */
+    sd   x23, 56(x10)  /* Save S7.  */
+    sd   x24, 64(x10)  /* Save S8.  */
+    sd   x25, 72(x10)  /* Save S9.  */
+    sd   x26, 80(x10)  /* Save S10. */
+    sd   x27, 88(x10)  /* Save S11. */
 
     /* Return the stack pointer. */