Add riscv64 support for apex prebuilt

This add support for src field in bp file.

Signed-off-by: Chen Guoyin <chenguoyin.cgy@linux.alibaba.com>
Signed-off-by: Mao Han <han_mao@linux.alibaba.com>
Change-Id: I9393696951db375d53436f9d5a9841b6a072cea3
diff --git a/apex/prebuilt.go b/apex/prebuilt.go
index 0f57911..70308c8 100644
--- a/apex/prebuilt.go
+++ b/apex/prebuilt.go
@@ -500,6 +500,9 @@
 		Arm64 struct {
 			Src *string `android:"path"`
 		}
+		Riscv64 struct {
+			Src *string `android:"path"`
+		}
 		X86 struct {
 			Src *string `android:"path"`
 		}
@@ -527,6 +530,8 @@
 		src = String(p.Arch.Arm.Src)
 	case android.Arm64:
 		src = String(p.Arch.Arm64.Src)
+	case android.Riscv64:
+		src = String(p.Arch.Riscv64.Src)
 	case android.X86:
 		src = String(p.Arch.X86.Src)
 	case android.X86_64: