[MFD] Fix gcc4 build errors in ucb1x00-core.c

drivers/mfd/ucb1x00-core.c:555: error: static declaration of 'ucb1x00_class' follows non-static declaration
drivers/mfd/ucb1x00.h:109: error: previous declaration of 'ucb1x00_class' was here

Since ucb1x00_class isn't used by anything, remove the extern
declaration and the symbol export.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/mfd/ucb1x00-core.c

@@ -642,8 +642,6 @@ static void __exit ucb1x00_exit(void)
 module_init(ucb1x00_init);
 module_exit(ucb1x00_exit);
 
-EXPORT_SYMBOL(ucb1x00_class);
-
 EXPORT_SYMBOL(ucb1x00_io_set_dir);
 EXPORT_SYMBOL(ucb1x00_io_write);
 EXPORT_SYMBOL(ucb1x00_io_read);

drivers/mfd/ucb1x00.h

@@ -106,8 +106,6 @@ struct ucb1x00_irq {
 	void (*fn)(int, void *);
 };
 
-extern struct class ucb1x00_class;
-
 struct ucb1x00 {
 	spinlock_t		lock;
 	struct mcp		*mcp;