i2c: sh7760: fix IRQ error path

While adding the invalid IRQ check after calling platform_get_irq(),
I managed to overlook that the driver has a complex error path in its
probe() method, thus a simple *return* couldn't be used.  Use a proper
*goto* instead!

Fixes: e5b2e3e7 ("i2c: sh7760: add IRQ check")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omprussia.ru>
Signed-off-by: Wolfram Sang <wsa@kernel.org>