media: pci: ivtv: Fix a sleep-in-atomic-context bug in ivtv_yuv_init()

The driver may sleep in a interrupt handler.

The function call paths (from bottom to top) in Linux-4.16 are:

[FUNC] kzalloc(GFP_KERNEL)
drivers/media/pci/ivtv/ivtv-yuv.c, 938:
	kzalloc in ivtv_yuv_init
drivers/media/pci/ivtv/ivtv-yuv.c, 960:
	ivtv_yuv_init in ivtv_yuv_next_free
drivers/media/pci/ivtv/ivtv-yuv.c, 1126:
	ivtv_yuv_next_free in ivtv_yuv_setup_stream_frame
drivers/media/pci/ivtv/ivtv-irq.c, 827:
	ivtv_yuv_setup_stream_frame in ivtv_irq_dec_data_req
drivers/media/pci/ivtv/ivtv-irq.c, 1013:
	ivtv_irq_dec_data_req in ivtv_irq_handler

To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC.

This bug is found by my static analysis tool DSAC.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>