[SPARC64]: Fix two year old bug in early bootup asm.

We try to fetch the CIF entry pointer from %o4, but that
can get clobbered by the early OBP calls.  It is saved
in %l7 already, so actually this "mov %o4, %l7" can just
be completely removed with no other changes.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc64/kernel/head.S

@@ -458,7 +458,6 @@ tlb_fixup_done:
 	or	%g6, %lo(init_thread_union), %g6
 	ldx	[%g6 + TI_TASK], %g4
 	mov	%sp, %l6
-	mov	%o4, %l7
 
 	wr	%g0, ASI_P, %asi
 	mov	1, %g1