x86/config: Fix warning for 'make ARCH=x86_64 tinyconfig'

Kconfig emits a warning for the following command:

  $ make ARCH=x86_64 tinyconfig
  ...
  .config:1380:warning: override: UNWINDER_GUESS changes choice state

When X86_64=y, the unwinder is exclusively selected from the following
three options:

 - UNWINDER_ORC
 - UNWINDER_FRAME_POINTER
 - UNWINDER_GUESS

However, arch/x86/configs/tiny.config only specifies the values of the
last two. UNWINDER_ORC must be explicitly disabled.

Signed-off-by: Masahiro Yamada <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: masahir0y

arch/x86/configs/tiny.config

@@ -1,5 +1,6 @@
 CONFIG_NOHIGHMEM=y
 # CONFIG_HIGHMEM4G is not set
 # CONFIG_HIGHMEM64G is not set
+# CONFIG_UNWINDER_ORC is not set
 CONFIG_UNWINDER_GUESS=y
 # CONFIG_UNWINDER_FRAME_POINTER is not set