of: fix clang -Wunsequenced for be32_to_cpu()

Now, make the loop explicit to avoid clang warning.

./include/linux/of.h:238:37: warning: multiple unsequenced modifications
to 'cell' [-Wunsequenced]
r = (r << 32) | be32_to_cpu(*(cell++));
^~
./include/linux/byteorder/generic.h:95:21: note: expanded from macro
'be32_to_cpu'
^
./include/uapi/linux/byteorder/little_endian.h:40:59: note: expanded
from macro '__be32_to_cpu'
^
./include/uapi/linux/swab.h:118:21: note: expanded from macro '__swab32'
___constant_swab32(x) : \
^
./include/uapi/linux/swab.h:18:12: note: expanded from macro
'___constant_swab32'
(((__u32)(x) & (__u32)0x000000ffUL) << 24) | \
^

Signed-off-by: Phong Tran <[e-mail]>
Reported-by: Nick Desaulniers <[e-mail]>
Link: https://github.com/ClangBuiltLinux/linux/issues/460
Suggested-by: David Laight <[e-mail]>
Reviewed-by: Nick Desaulniers <[e-mail]>
Cc: [e-mail]
[robh: fix up whitespace]
Signed-off-by: Rob Herring <[e-mail]>

include/linux/of.h

···
 static inline u64 of_read_number(const __be32 *cell, int size)
 {
 	u64 r = 0;
-	while (size--)
-		r = (r << 32) | be32_to_cpu(*(cell++));
+	for (; size--; cell++)
+		r = (r << 32) | be32_to_cpu(*cell);
 	return r;
 }