powerpc: Add const qual to local_read() parameter

A patch in net-next triggered a compile error on powerpc:

include/linux/u64_stats_sync.h: In function 'u64_stats_read':
include/asm-generic/local64.h:30:37: warning: passing argument 1 of 'local_read' discards 'const' qualifier from pointer target type

This seems reasonable to relax powerpc local_read() requirements.

Fixes: 316580b69d0a ("u64_stats: provide u64_stats_t type")
Signed-off-by: Eric Dumazet <[e-mail]>
Reported-by: kbuild test robot <[e-mail]>
Acked-by: Michael Ellerman <[e-mail]>
Tested-by: Stephen Rothwell <[e-mail]> # build only
Signed-off-by: Jakub Kicinski <[e-mail]>

arch/powerpc/include/asm/local.h

···
 
 #define LOCAL_INIT(i)	{ (i) }
 
-static __inline__ long local_read(local_t *l)
+static __inline__ long local_read(const local_t *l)
 {
 	return READ_ONCE(l->v);
 }