parisc: Allow live-patching of __meminit functions

When making the text sections writeable with set_kernel_text_rw(1),
include all text sections including those in the __init section.
Otherwise functions marked with __meminit will stay read-only.
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org>	# 4.20+

arch/parisc/mm/init.c

@@ -478,7 +478,7 @@ static void __init map_pages(unsigned long start_vaddr,
 
 void __init set_kernel_text_rw(int enable_read_write)
 {
-	unsigned long start = (unsigned long) _text;
+	unsigned long start = (unsigned long) __init_begin;
 	unsigned long end   = (unsigned long) &data_start;
 
 	map_pages(start, __pa(start), end-start,