Use filegroup as genrule srcs.

Test: mmma hardware/interfaces -j64
Change-Id: If282ed5f4a87045d169fcea7ad648b046a5f1cfb
diff --git a/boot/1.0/Android.bp b/boot/1.0/Android.bp
index 9dcabc4..7265cc2 100644
--- a/boot/1.0/Android.bp
+++ b/boot/1.0/Android.bp
@@ -13,8 +13,7 @@
     tools: ["hidl-gen"],
     cmd: "$(location hidl-gen) -o $(genDir) -Lc++ -randroid.hardware:hardware/interfaces -randroid.hidl:system/libhidl/transport android.hardware.boot@1.0",
     srcs: [
-        "types.hal",
-        "IBootControl.hal",
+        ":android.hardware.boot@1.0_hal",
     ],
     out: [
         "android/hardware/boot/1.0/types.cpp",
@@ -27,8 +26,7 @@
     tools: ["hidl-gen"],
     cmd: "$(location hidl-gen) -o $(genDir) -Lc++ -randroid.hardware:hardware/interfaces -randroid.hidl:system/libhidl/transport android.hardware.boot@1.0",
     srcs: [
-        "types.hal",
-        "IBootControl.hal",
+        ":android.hardware.boot@1.0_hal",
     ],
     out: [
         "android/hardware/boot/1.0/types.h",