s3c-hsudc: Fix possible nullpointer dereference during probe

The usb-interrupt is requested before the endpoints are initalised.
If an interrupt happens in the time between request_irq and the init
of the endpoint-data (as seen on the Qisda ESx00 ebook-platforms),
it is therefore possible for the interrupt handler to access endpoint-
data before its creation resulting in a null-pointer dereference.

This patch simply moves the irq request below the endpoint init.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>