powerpc/32: Remove CLR_TOP32

CLR_TOP32() is defined as blank. Last useful instance of CLR_TOP32()
was removed by commit 40ef8cbc ("powerpc: Get 64-bit configs to
compile with ARCH=powerpc") in 2005.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/ppc_asm.h

@@ -511,7 +511,6 @@ END_FTR_SECTION_IFCLR(CPU_FTR_601)
 #endif
 #define MTMSRD(r)	mtmsr	r
 #define MTMSR_EERI(reg)	mtmsr	reg
-#define CLR_TOP32(r)
 #endif
 
 #endif /* __KERNEL__ */

arch/powerpc/kernel/entry_32.S

@@ -654,7 +654,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_SPE)
 #endif /* CONFIG_SMP */
 
 	tophys(r0,r4)
-	CLR_TOP32(r0)
 	mtspr	SPRN_SPRG_THREAD,r0	/* Update current THREAD phys addr */
 	lwz	r1,KSP(r4)	/* Load new stack pointer */
 

arch/powerpc/kernel/head_32.S

@@ -266,7 +266,6 @@ __secondary_hold_acknowledge:
 
 
 #define EXCEPTION_PROLOG_2	\
-	CLR_TOP32(r11);		\
 	stw	r10,_CCR(r11);		/* save registers */ \
 	stw	r12,GPR12(r11);	\
 	stw	r9,GPR9(r11);	\
@@ -862,7 +861,6 @@ __secondary_start:
 	/* ptr to phys current thread */
 	tophys(r4,r2)
 	addi	r4,r4,THREAD	/* phys address of our thread_struct */
-	CLR_TOP32(r4)
 	mtspr	SPRN_SPRG_THREAD,r4
 	li	r3,0
 	mtspr	SPRN_SPRG_RTAS,r3	/* 0 => not in RTAS */
@@ -949,7 +947,6 @@ start_here:
 	/* ptr to phys current thread */
 	tophys(r4,r2)
 	addi	r4,r4,THREAD	/* init task's THREAD */
-	CLR_TOP32(r4)
 	mtspr	SPRN_SPRG_THREAD,r4
 	li	r3,0
 	mtspr	SPRN_SPRG_RTAS,r3	/* 0 => not in RTAS */

arch/powerpc/kernel/head_8xx.S

@@ -151,7 +151,6 @@ turn_on_mmu:
 
 
 #define EXCEPTION_PROLOG_2	\
-	CLR_TOP32(r11);		\
 	stw	r10,_CCR(r11);		/* save registers */ \
 	stw	r12,GPR12(r11);	\
 	stw	r9,GPR9(r11);	\