HID: hid-appletb-kbd: simplify logic used to switch between media and function...

HID: hid-appletb-kbd: simplify logic used to switch between media and function keys on pressing fn key

This commit simplifies the logic in appletb_kbd_inp_event used for
switching between the media and function keys on pressing the fn key.

We now also prevent touching the kbd->saved_mode variable in case the esc
key only mode is chosen.

The following small fixes have also been done in this patch:

- A small comment style error has been fixed
- Fixed spelling in MODULE_DESCRIPTION
- I have added myself to MODULE_AUTHOR

Signed-off-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>