[msp430] support sym+int and sym-sym

[DJ Delorie]

Because sizeof(void*) is 4 but POINTER_SIZE is 3, we have to handle
some things manually.  This is yet another one.  Committed.

        * config/msp430/msp430.c (msp430_asm_integer): Support addition
        and subtraction too.

Index: config/msp430/msp430.c
===================================================================
--- config/msp430/msp430.c      (revision 224181)
+++ config/msp430/msp430.c      (working copy)
@@ -973,13 +973,14 @@ msp430_asm_integer (rtx x, unsigned int 
   if (size == 3 && GET_MODE (x) == PSImode)
     size = 4;
 
   switch (size)
     {
     case 4:
-      if (c == SYMBOL_REF || c == CONST || c == LABEL_REF || c == CONST_INT)
+      if (c == SYMBOL_REF || c == CONST || c == LABEL_REF || c == CONST_INT
+         || c == PLUS || c == MINUS)
        {
          fprintf (asm_out_file, "\t.long\t");
          output_addr_const (asm_out_file, x);
          fputc ('\n', asm_out_file);
          return true;
        }