wil6210: rename [en|dis]able irq to [un]mask

To better reflect real action performed, rename:
s/wil6210_disable_irq/wil_mask_irq/
s/wil6210_enable_irq/wil_unmask_irq/

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>