macintosh: Use kmemdup rather than duplicating its implementation

kmemdup is introduced to duplicate a region of memory in a neat way.
Rather than kmalloc/kzalloc + memcpy, which the programmer needs to
write the size twice (sometimes lead to mistakes), kmemdup improves
readability, leads to smaller code and also reduce the chances of mistakes.
Suggestion to use kmemdup rather than using kmalloc/kzalloc + memcpy.

Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
[chleroy: Fixed parenthesis alignment]
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190703162821.32322-1-huangfq.daxian@gmail.com

drivers/macintosh/adbhid.c

@@ -789,7 +789,8 @@ adbhid_input_register(int id, int default_id, int original_handler_id,
 
 	switch (default_id) {
 	case ADB_KEYBOARD:
-		hid->keycode = kmalloc(sizeof(adb_to_linux_keycodes), GFP_KERNEL);
+		hid->keycode = kmemdup(adb_to_linux_keycodes,
+				       sizeof(adb_to_linux_keycodes), GFP_KERNEL);
 		if (!hid->keycode) {
 			err = -ENOMEM;
 			goto fail;
@@ -797,8 +798,6 @@ adbhid_input_register(int id, int default_id, int original_handler_id,
 
 		sprintf(hid->name, "ADB keyboard");
 
-		memcpy(hid->keycode, adb_to_linux_keycodes, sizeof(adb_to_linux_keycodes));
-
 		switch (original_handler_id) {
 		default:
 			keyboard_type = "<unknown>";