V4L/DVB (5917): ivtv: improve mailbox responsiveness.
V4L/DVB (5917): ivtv: improve mailbox responsiveness.

First try polling for the result of a mailbox command, then
switch to a test/sleep loop. Also reduce the sleep time from 10 ms
to 1 ms. Improves the responsiveness of the mailbox handling.

Signed-off-by: Hans Verkuil <f625be9dbdcbbd12a043857af148e8fb895d9a1d@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <ad86ba2154032c9f55743a190faa2459a9d61d42@infradead.org>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs