powerpc: Remove NULL task struct pointer checks in FP and vector code

We used to allow giveup_*() to be called with a NULL task struct
pointer. Now those cases are handled in the caller we can remove
the checks. We can also remove giveup_altivec_notask() which is also
unused.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/switch_to.h

@@ -38,7 +38,6 @@ static inline void giveup_fpu(struct task_struct *t) { }
 #ifdef CONFIG_ALTIVEC
 extern void flush_altivec_to_thread(struct task_struct *);
 extern void giveup_altivec(struct task_struct *);
-extern void giveup_altivec_notask(void);
 #else
 static inline void flush_altivec_to_thread(struct task_struct *t)
 {

arch/powerpc/kernel/fpu.S

@@ -173,8 +173,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX)
 	MTMSRD(r5)			/* enable use of fpu now */
 	SYNC_601
 	isync
-	PPC_LCMPI	0,r3,0
-	beqlr-				/* if no previous owner, done */
 	addi	r3,r3,THREAD	        /* want THREAD of task */
 	PPC_LL	r6,THREAD_FPSAVEAREA(r3)
 	PPC_LL	r5,PT_REGS(r3)

arch/powerpc/kernel/head_fsl_booke.S

@@ -992,8 +992,6 @@ _GLOBAL(giveup_spe)
 	oris	r5,r5,MSR_SPE@h
 	mtmsr	r5			/* enable use of SPE now */
 	isync
-	cmpi	0,r3,0
-	beqlr-				/* if no previous owner, done */
 	addi	r3,r3,THREAD		/* want THREAD of task */
 	lwz	r5,PT_REGS(r3)
 	cmpi	0,r5,0

arch/powerpc/kernel/vector.S

@@ -111,16 +111,6 @@ _GLOBAL(load_up_altivec)
 	/* restore registers and return */
 	blr
 
-_GLOBAL(giveup_altivec_notask)
-	mfmsr	r3
-	andis.	r4,r3,MSR_VEC@h
-	bnelr				/* Already enabled? */
-	oris	r3,r3,MSR_VEC@h
-	SYNC
-	MTMSRD(r3)			/* enable use of VMX now */
-	isync
-	blr
-
 /*
  * giveup_altivec(tsk)
  * Disable VMX for the task given as the argument,
@@ -133,8 +123,6 @@ _GLOBAL(giveup_altivec)
 	SYNC
 	MTMSRD(r5)			/* enable use of VMX now */
 	isync
-	PPC_LCMPI	0,r3,0
-	beqlr				/* if no previous owner, done */
 	addi	r3,r3,THREAD		/* want THREAD of task */
 	PPC_LL	r7,THREAD_VRSAVEAREA(r3)
 	PPC_LL	r5,PT_REGS(r3)
@@ -203,8 +191,6 @@ _GLOBAL(__giveup_vsx)
 	mtmsrd	r5			/* enable use of VSX now */
 	isync
 
-	cmpdi	0,r3,0
-	beqlr-				/* if no previous owner, done */
 	addi	r3,r3,THREAD		/* want THREAD of task */
 	ld	r5,PT_REGS(r3)
 	cmpdi	0,r5,0