powerpc/mm/32s: fix condition that is always true

Move a misplaced paren that makes the condition always true.

Fixes: 63b2bc61 ("powerpc/mm/32s: Use BATs for STRICT_KERNEL_RWX")
Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/mm/pgtable_32.c

@@ -365,7 +365,7 @@ void mark_initmem_nx(void)
 	unsigned long numpages = PFN_UP((unsigned long)_einittext) -
 				 PFN_DOWN((unsigned long)_sinittext);
 
-	if (v_block_mapped((unsigned long)_stext) + 1)
+	if (v_block_mapped((unsigned long)_stext + 1))
 		mmu_mark_initmem_nx();
 	else
 		change_page_attr(page, numpages, PAGE_KERNEL);