enabling thumb only enter user mode in tmr-ints.

usermode breaks rftests.

tests/tmr-ints.c

@@ -124,8 +124,10 @@ void main(void) {
 
 	/* go into user mode to handle IRQs */
 	/* disabling interrupts is now difficult */
- 	asm("msr     cpsr_c,#(0x10)");
-
+ 	asm(".code 32;"
+	    "msr     cpsr_c,#(0x10);"
+	    ".code 16; ");
+	
 	while(1) {
 		/* sit here and let the interrupts do the work */
 	};