media: pvrusb2: drop unexpected word 'a' in comments

there is an unexpected word 'a' in the comments that need to be dropped

file - drivers/media/usb/pvrusb2/pvrusb2-hdw.c
line - 5044

But now it's a a chicken and egg problem...) */

changed to:

But now it's a chicken and egg problem...) */

Signed-off-by: Jiang Jian <jiangjian@cdjrlc.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>