power: supply: test-power: use strscpy() instead of strncpy()

The implementation of strscpy() is more robust and safer.
That's now the recommended way to copy NUL-terminated strings.

Signed-off-by: Xu Panda <[e-mail]>
Signed-off-by: Yang Yang <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>

drivers/power/supply/test_power.c

···
 	char buf[MAX_KEYLENGTH];
 	int cr;
 
-	strncpy(buf, key, MAX_KEYLENGTH);
-	buf[MAX_KEYLENGTH-1] = '\0';
+	strscpy(buf, key, MAX_KEYLENGTH);
 
 	cr = strnlen(buf, MAX_KEYLENGTH) - 1;
 	if (cr < 0)