powerpc/feature: Use CONFIG_PPC64 instead of __powerpc64__ to define possible features

In order to build VDSO32 for PPC64, we need to have CPU_FTRS_POSSIBLE
and CPU_FTRS_ALWAYS independant of whether we are building the
32 bits VDSO or the 64 bits VDSO.

Use #ifdef CONFIG_PPC64 instead of #ifdef __powerpc64__
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126131006.2431205-1-mpe@ellerman.id.au

arch/powerpc/include/asm/cputable.h

@@ -488,7 +488,7 @@ static inline void cpu_feature_keys_init(void) { }
 	    CPU_FTR_PURR | CPU_FTR_REAL_LE | CPU_FTR_DABRX)
 #define CPU_FTRS_COMPATIBLE	(CPU_FTR_PPCAS_ARCH_V2)
 
-#ifdef __powerpc64__
+#ifdef CONFIG_PPC64
 #ifdef CONFIG_PPC_BOOK3E
 #define CPU_FTRS_POSSIBLE	(CPU_FTRS_E6500 | CPU_FTRS_E5500)
 #else
@@ -545,7 +545,7 @@ enum {
 };
 #endif /* __powerpc64__ */
 
-#ifdef __powerpc64__
+#ifdef CONFIG_PPC64
 #ifdef CONFIG_PPC_BOOK3E
 #define CPU_FTRS_ALWAYS		(CPU_FTRS_E6500 & CPU_FTRS_E5500)
 #else