scull: replace deprecated CFLAGS with ccflags-y in Makefile.
Get scull to compile cleanly.

The main changes were replacing the removed init_MUTEX and struct
file_operations ioctl ops.
misc-modules: clean up hello.
misc-progs: Clean up setlevel.
misc-progs: clean up setconsole.
scull: clean up header.
scull: clean up main.
scull: clean up scull_load.
scull: clean up scull_unload.
scull: clean up scull.init.