x86/olpc: select GPIOLIB_LEGACY

The OLPC GPIO controller sets up a fixed number space that is used
by at least two drivers:

arch/x86/platform/olpc/olpc-xo1-sci.c: In function 'setup_ec_sci':
arch/x86/platform/olpc/olpc-xo1-sci.c:358:13: error: implicit declaration of function 'gpio_request' [-Wimplicit-function-declaration]
  358 |         r = gpio_request(OLPC_GPIO_ECSCI, "OLPC-ECSCI");
      |             ^~~~~~~~~~~~
sound/pci/cs5535audio/cs5535audio_olpc.c: In function 'olpc_analog_input':
sound/pci/cs5535audio/cs5535audio_olpc.c:41:9: error: implicit declaration of function 'gpio_set_value'; did you mean 'gpiod_set_value'? [-Wimplicit-function-declaration]
   41 |         gpio_set_value(OLPC_GPIO_MIC_AC, on);

The AMD Geode platform that this is based on is now marked as
'Orphaned' in Kconfig, and it is likely that there are no XO1
users on modern kernels, but so far there is no consensus on
removing it entirely.

Select CONFIG_GPIOLIB_LEGACY for this platform and make sure the
sound driver portion cannot be compiled without this.

Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> # for input
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/x86/Kconfig

@@ -2976,6 +2976,7 @@ config OLPC
 	bool "One Laptop Per Child support"
 	depends on !X86_PAE
 	select GPIOLIB
+	select GPIOLIB_LEGACY
 	select OF
 	select OF_PROMTREE
 	select IRQ_DOMAIN

arch/x86/platform/olpc/olpc-xo1-sci.c

@@ -9,7 +9,7 @@
 
 #include <linux/cs5535.h>
 #include <linux/device.h>
-#include <linux/gpio.h>
+#include <linux/gpio/legacy.h>
 #include <linux/input.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>

sound/pci/Kconfig

@@ -300,6 +300,7 @@ config SND_CS5535AUDIO
 	tristate "CS5535/CS5536 Audio"
 	depends on X86_32 || MIPS || COMPILE_TEST
 	depends on HAS_IOPORT
+	depends on GPIOLIB_LEGACY || !OLPC
 	select SND_PCM
 	select SND_AC97_CODEC
 	help

sound/pci/cs5535audio/cs5535audio_olpc.c

@@ -9,7 +9,7 @@
 #include <sound/info.h>
 #include <sound/control.h>
 #include <sound/ac97_codec.h>
-#include <linux/gpio.h>
+#include <linux/gpio/legacy.h>
 
 #include <asm/olpc.h>
 #include "cs5535audio.h"