drm/tiny: Kconfig: Remove always-y THERMAL dep. from TINYDRM_REPAPER

Commit 554b3529 ("thermal/drivers/core: Remove the module Kconfig's
option") changed the type of THERMAL from tristate to bool, so
THERMAL || !THERMAL is now always y. Remove the redundant dependency.

Discovered through Kconfiglib detecting a dependency loop. The C tools
simplify the expression to y before running dependency loop detection,
and so don't see it. Changing the type of THERMAL back to tristate makes
the C tools detect the same loop.

Not sure if running dep. loop detection after simplification can be
called a bug. Fixing this nit unbreaks Kconfiglib on the kernel at
least.

Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190927174218.GA32085@huvuddator