powerpc/mmu: Don't duplicate radix_enabled()

mmu_has_feature(MMU_FTR_TYPE_RADIX) can be evaluated regardless of
CONFIG_PPC_RADIX_MMU.

When CONFIG_PPC_RADIX_MMU is not set, mmu_has_feature(MMU_FTR_TYPE_RADIX)
will evaluate to 'false' at build time because MMU_FTR_TYPE_RADIX
wont be included in MMU_FTRS_POSSIBLE.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/62743846cbd493e5d9a02e197c2672a1d30df149.1620366342.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/mmu.h

@@ -324,7 +324,6 @@ static inline void assert_pte_locked(struct mm_struct *mm, unsigned long addr)
 }
 #endif /* !CONFIG_DEBUG_VM */
 
-#ifdef CONFIG_PPC_RADIX_MMU
 static inline bool radix_enabled(void)
 {
 	return mmu_has_feature(MMU_FTR_TYPE_RADIX);
@@ -334,17 +333,6 @@ static inline bool early_radix_enabled(void)
 {
 	return early_mmu_has_feature(MMU_FTR_TYPE_RADIX);
 }
-#else
-static inline bool radix_enabled(void)
-{
-	return false;
-}
-
-static inline bool early_radix_enabled(void)
-{
-	return false;
-}
-#endif
 
 #ifdef CONFIG_STRICT_KERNEL_RWX
 static inline bool strict_kernel_rwx_enabled(void)