vt: Clear selection before changing the font

In the Linux kernel, the following vulnerability has been resolved: vt: Clear selection before changing the font When changing the console font with ioctl(KDFONTOP) the new font size can be bigger than the previous font. A previous selection may thus now be outside of the new screen size and thus trigger out-of-bounds accesses to graphics memory if the selection is removed in vc_do_resize(). Prevent such out-of-memory accesses by dropping the selection before the various con_font_set() console handlers are called.