RISC-V: Fix .init section permission update

.init section permission should only updated to non-execute if
STRICT_KERNEL_RWX is enabled. Otherwise, this will lead to a kernel hang.

Fixes: 19a00869 ("RISC-V: Protect all kernel sections including init early")
Cc: stable@vger.kernel.org
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

arch/riscv/kernel/setup.c

@@ -293,6 +293,8 @@ void free_initmem(void)
 	unsigned long init_begin = (unsigned long)__init_begin;
 	unsigned long init_end = (unsigned long)__init_end;
 
-	set_memory_rw_nx(init_begin, (init_end - init_begin) >> PAGE_SHIFT);
+	if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
+		set_memory_rw_nx(init_begin, (init_end - init_begin) >> PAGE_SHIFT);
+
 	free_initmem_default(POISON_FREE_INITMEM);
 }