Thumb2 BL disassembly broken

[Yifan Lu]

(Dup of yifanlu#1)

Sample sequence (test.bin)

FF F7 54 FF 00 BF 00 BF 70 47

Disassembly

   0:	f7ff ff54 	bl	0xfffffeac
   4:	bf00      	nop
   6:	bf00      	nop
   8:	4770      	bx	lr

./test-transform-dis-thumb2 manual 8 1 < test.bin produces

#if 0
transform_dis (0x10000): branch => 0xfe80fd54
transform_dis (0x10000): >> op_size=4 newop_size=4
=> 3
#endif