fbdev.node converted from kdev_t to int - all of its users
have register_framebuffer() which sets .node to mk_kdev(FB_MAJOR, index)
already called and all of them start with applying minor().  IOW, what
they actually want is framebuffer number.

	* type of ->node changed to int
	* register_framebuffer() sets it to index instead of mk_kdev(...)
	* users converted from minor(foo.node) to foo.node
	* useless assignments (typically to NODEV) removed - we never
look at that field before register_framebuffer() overwrites it and thus
any assignments prior to register_framebuffer() call are dead code.