HID: prodikeys: make array keys static const, makes object smaller

Don't populate the array keys on the stack but instead make it
static const. Makes the object code smaller by 166 bytes.

Before:
text data bss dec hex filename
18931 5872 480 25283 62c3 drivers/hid/hid-prodikeys.o

After:
text data bss dec hex filename
18669 5968 480 25117 621d drivers/hid/hid-prodikeys.o

(gcc version 9.2.1, amd64)

Signed-off-by: Colin Ian King <[e-mail]>
Signed-off-by: Jiri Kosina <[e-mail]>

drivers/hid/hid-prodikeys.c

···
 		MY PICTURES =>	KEY_WORDPROCESSOR
 		MY MUSIC=>	KEY_SPREADSHEET
 	*/
-	unsigned int keys[] = {
+	static const unsigned int keys[] = {
 		KEY_FN,
 		KEY_MESSENGER, KEY_CALENDAR,
 		KEY_ADDRESSBOOK, KEY_DOCUMENTS,
···
 		0
 	};
 
-	unsigned int *pkeys = &keys[0];
+	const unsigned int *pkeys = &keys[0];
 	unsigned short i;
 
 	if (pm->ifnum != 1)  /* only set up ONCE for interace 1 */