LoongArch: Drop these obsolete selects in Kconfig

LoongArch: Drop these obsolete selects in Kconfig

Commit 740b41dc45ee ("LoongArch: Add build infrastructure") adds the new
file arch/loongarch/Kconfig.

As the work on LoongArch was probably quite some time under development,
various config symbols have changed and disappeared from the time of
initial writing of the Kconfig file and its inclusion in the repository.

The following four commits:

  commit f99a1bd51b31 ("arch: remove GENERIC_FIND_FIRST_BIT entirely")
  commit 9bd2ac1d77ea ("arch: remove HAVE_COPY_THREAD_TLS")
  commit 82eeb04859ca ("mm: remove CONFIG_HAVE_MEMBLOCK")
  commit b4cbc1ce8cc5 ("mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option")

remove the mentioned config symbol, and enable the intended setup by
default without configuration.

Drop these obsolete selects in loongarch's Kconfig.

Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>