usb_modeswitch: bump to version 1.2.6

Remove 'usb_modeswitch-makefile.patch' because it was merged upstream.

This package contains a dispatcher (wrapper) that can be installed as Tcl
script or as binary without further dependency.  If Tcl is selected and the
binary interpreter is installed (BR2_PACKAGE_TCL &&
!BR2_PACKAGE_TCL_SHLIB_ONLY) the dispatcher will be installed as Tcl script
otherwise as binary.

Signed-off-by: Patrick Ziegler <patrick.ziegler@fh-kl.de>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>