gallium/nouveau: fully build the driver under android

Fix the trivial typo in the variable name.

Cc: "10.2 10.3" <mesa-stable@lists.freedesktop.org>
diff --git a/src/gallium/drivers/nouveau/Android.mk b/src/gallium/drivers/nouveau/Android.mk
index 5870aa0..3f6ec5b 100644
--- a/src/gallium/drivers/nouveau/Android.mk
+++ b/src/gallium/drivers/nouveau/Android.mk
@@ -32,7 +32,7 @@
 	$(C_SOURCES) \
 	$(NV30_C_SOURCES) \
 	$(NV50_CODEGEN_SOURCES) \
-	$(NV50_C_SOURES) \
+	$(NV50_C_SOURCES) \
 	$(NVC0_CODEGEN_SOURCES) \
 	$(NVC0_C_SOURCES)