media: fix media Kconfig help syntax issues

The help text should be indented by at least two spaces after the
'help' separator. This is both good practice and the media_build system
for building media drivers makes this assumption.

I went through all Kconfigs under drivers/media and fixed any bad help
sections. This makes it conform to the common practice and should fix
problems with 'make menuconfig' when using media_build. This is due to
a "WARNING" message that media_build can insert in the Kconfig and that
assumes the help text is indented by at least two spaces. If not, then the
Kconfig becomes invalid and 'make menuconfig' fails.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reported-by: Thomas Kaiser <linux-dvb@kaiser-linux.li>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>