x86/fpu: Replace the includes of fpu/internal.h

x86/fpu: Replace the includes of fpu/internal.h

BugLink: https://bugs.launchpad.net/bugs/1967750
Now that the file is empty, fixup all references with the proper includes
and delete the former kitchen sink.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211015011540.001197214@linutronix.de
(cherry picked from commit b56d2795b29792c465cc8ef036abad5127a003fb)
Acked-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>