media: b2c2: Remove unused functions

flexcop_dma_control_size_irq() last use was removed in 2005 by
commit 64221be7 ("[PATCH] dvb: flexcop: woraround irq stop problem")

flexcop_dump_reg() last use was removed in 2009 by
commit 382c5546 ("V4L/DVB (10694): [PATCH] software IRQ watchdog for
Flexcop B2C2 DVB PCI cards")

Remove them.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>