powerpc: Move the testing of CPU_FTR_COHERENT_ICACHE into __flush_icache_range

In function flush_icache_range(), we use cpu_has_feature() to test
the feature bit of CPU_FTR_COHERENT_ICACHE. But this seems not optimal
for two reasons:
 a) For ppc32, the function __flush_icache_range() already do this
    check with the macro END_FTR_SECTION_IFSET.
 b) Compare with the cpu_has_feature(), the method of using macro
    END_FTR_SECTION_IFSET will not introduce any runtime overhead.

[And while at it, add the missing required isync] -- BenH
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/cacheflush.h

@@ -35,7 +35,6 @@ extern void __flush_disable_L1(void);
 extern void __flush_icache_range(unsigned long, unsigned long);
 static inline void flush_icache_range(unsigned long start, unsigned long stop)
 {
-	if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
 	__flush_icache_range(start, stop);
 }
 

arch/powerpc/kernel/misc_32.S

@@ -329,6 +329,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_UNIFIED_ID_CACHE)
  */
 _KPROBE(__flush_icache_range)
 BEGIN_FTR_SECTION
+	isync
 	blr				/* for 601, do nothing */
 END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
 	li	r5,L1_CACHE_BYTES-1

arch/powerpc/kernel/misc_64.S

@@ -68,7 +68,9 @@ PPC64_CACHES:
  */
 
 _KPROBE(__flush_icache_range)
-
+BEGIN_FTR_SECTION
+	blr
+END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
 /*
  * Flush the data cache to memory 
  *