SimonQian <simonqian@SimonQian.com>:

Add svf_get_mask_u32 to generate a mask according to bitlen.
Fix this bug in other functions except for svf_check_tdo.


git-svn-id: svn://svn.berlios.de/openocd/trunk@1914 b42882b7-edfa-0310-969c-e2dbd0fdcd60