of: module: remove strlen() call in of_modalias()

In of_modalias(), there's no dire need to call strlen() (and then add 1
to its result to account for the 'C' char preceding the compat string).
Replace that strlen() with snprintf() (currently below it) -- this way,
we always try to print the compat string but then only advance the str
and len parameters iff the compat string fit into the remaining buffer
space...

Signed-off-by: Sergey Shtylyov <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rob Herring (Arm) <[e-mail]>

drivers/of/module.c

···
 	str += csize;
 
 	of_property_for_each_string(np, "compatible", p, compat) {
-		csize = strlen(compat) + 1;
+		csize = snprintf(str, len, "C%s", compat);
 		tsize += csize;
 		if (csize >= len)
 			continue;
-
-		csize = snprintf(str, len, "C%s", compat);
 		for (c = str; c; ) {
 			c = strchr(c, ' ');
 			if (c)