[PATCH] nouveau: fix build eror when VGA_SWITCHEROO is not enabled

[Randy Dunlap <rdunlap@infradead.org>]

From: Randy Dunlap <rdunlap@infradead.org>

Fix nouveau build error on x86, when ACPI is enabled but
VGA_SWITCHEROO is not enabled, by providing a stub function.

drivers/built-in.o: In function `nouveau_pmops_runtime_suspend':
nouveau_drm.c:(.text+0x3aac89): undefined reference to `nouveau_switcheroo_optimus_dsm'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
---
 drivers/gpu/drm/nouveau/nouveau_acpi.c |    1 +
 1 file changed, 1 insertion(+)

--- linux-next-20130911.orig/drivers/gpu/drm/nouveau/nouveau_acpi.c
+++ linux-next-20130911/drivers/gpu/drm/nouveau/nouveau_acpi.c
@@ -373,6 +373,7 @@ void nouveau_unregister_dsm_handler(void
 #else
 void nouveau_register_dsm_handler(void) {}
 void nouveau_unregister_dsm_handler(void) {}
+void nouveau_switcheroo_optimus_dsm(void) {}
 #endif
 
 /* retrieve the ROM in 4k blocks */