[POWERPC] Fix COMMON symbol warnings

We get the following warnings in various ARCH=powerpc builds:

WARNING: "ee_restarts" [arch/powerpc/kernel/built-in] is COMMON symbol
WARNING: "fee_restarts" [arch/powerpc/kernel/built-in] is COMMON symbol
WARNING: "htab_hash_searches" [arch/powerpc/mm/built-in] is COMMON symbol
WARNING: "next_slot" [arch/powerpc/mm/built-in] is COMMON symbol
WARNING: "mmu_hash_lock" [arch/powerpc/mm/built-in] is COMMON symbol
WARNING: "primary_pteg_full" [arch/powerpc/mm/built-in] is COMMON symbol
WARNING: "global_dbcr0" [arch/powerpc/kernel/built-in] is COMMON symbol

Switch to moving local symbols (except mmu_hash_lock which is global) and
space directive instead.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/kernel/entry_32.S

@@ -596,7 +596,11 @@ fast_exception_return:
 	mr	r12,r4		/* restart at exc_exit_restart */
 	b	2b
 
-	.comm	fee_restarts,4
+	.section .bss
+	.align	2
+fee_restarts:
+	.space	4
+	.previous
 
 /* aargh, a nonrecoverable interrupt, panic */
 /* aargh, we don't know which trap this is */
@@ -851,7 +855,11 @@ load_dbcr0:
 	mtspr	SPRN_DBSR,r11	/* clear all pending debug events */
 	blr
 
-	.comm	global_dbcr0,8
+	.section .bss
+	.align	4
+global_dbcr0:
+	.space	8
+	.previous
 #endif /* !(CONFIG_4xx || CONFIG_BOOKE) */
 
 do_work:			/* r10 contains MSR_KERNEL here */
@@ -926,7 +934,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_601)
 	/* shouldn't return */
 	b	4b
 
-	.comm	ee_restarts,4
+	.section .bss
+	.align	2
+ee_restarts:
+	.space	4
+	.previous
 
 /*
  * PROM code for specific machines follows.  Put it

arch/powerpc/mm/hash_low_32.S

@@ -30,7 +30,11 @@
 #include <asm/asm-offsets.h>
 
 #ifdef CONFIG_SMP
-	.comm	mmu_hash_lock,4
+	.section .bss
+	.align	2
+	.globl mmu_hash_lock
+mmu_hash_lock:
+	.space	4
 #endif /* CONFIG_SMP */
 
 /*
@@ -455,9 +459,15 @@ found_slot:
 	sync		/* make sure pte updates get to memory */
 	blr
 
-	.comm	next_slot,4
-	.comm	primary_pteg_full,4
-	.comm	htab_hash_searches,4
+	.section .bss
+	.align	2
+next_slot:
+	.space	4
+primary_pteg_full:
+	.space	4
+htab_hash_searches:
+	.space	4
+	.previous
 
 /*
  * Flush the entry for a particular page from the hash table.