tinyconfig: remove unnecessary 'is not set' for choice blocks

tinyconfig: remove unnecessary 'is not set' for choice blocks

This reverts the following commits:

 - 236dec051078 ("kconfig: tinyconfig: provide whole choice blocks to
   avoid warnings")

 - b0f269728ccd ("x86/config: Fix warning for 'make ARCH=x86_64
   tinyconfig'")

Since commit f79dc03fe68c ("kconfig: refactor choice value calculation"),
it is no longer necessary to disable the remaining options in choice
blocks.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>