powerpc/time: Remove ifdef in get_vtb()

SPRN_VTB and CPU_FTR_ARCH_207S are always defined,
no need of an ifdef.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a0fc81cd85121407726bcf480fc9a0d8e7617fce.1601549933.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/time.h

@@ -41,10 +41,9 @@ struct div_result {
 
 static inline u64 get_vtb(void)
 {
-#ifdef CONFIG_PPC_BOOK3S_64
 	if (cpu_has_feature(CPU_FTR_ARCH_207S))
 		return mfspr(SPRN_VTB);
-#endif
+
 	return 0;
 }