doc-rst: linux_tv: don't use uppercases for syscall sections

doc-rst: linux_tv: don't use uppercases for syscall sections

On the syscall conversions, we used uppercase for the sections,
but this is too bold. So, convert them to Camel Case, as it
looks visually better.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>