v4l2: streamline logic

v4l2: streamline logic

Move exiting path out of if (entering(tcp)) { ... return 0; } else,
provide common exit point in v4l2_ioctl handler, use break instead of
return in specific command handlers.

* v4l2.c (print_v4l2_format, print_v4l2_buffer, print_v4l2_standard,
print_v4l2_input, print_v4l2_frmivalenum): Move exiting path out of else
par of the entering(tcp) condition.
(v4l2_ioctl): Add return RVAL_DECODED | 1 at the end of function.
(v4l2_ioctl) <case VIDIOC_S_STD, case VIDIOC_S_INPUT>: Replace return
with break.