Revert "Add debug ramdisk variant"

This reverts commit f84e9c05e2103149162e4a78a68f20c164fbbba2.

Because this breaks the usage of boot-debug.img and
vendor_boot-debug.img

Bug: 185970130
Bug: 185990198
Test: make bootimage_debug
Change-Id: I7886c971982faae1d5bc34688643de8d94d6e201
diff --git a/android/arch.go b/android/arch.go
index 9f93752..20fcc95 100644
--- a/android/arch.go
+++ b/android/arch.go
@@ -617,7 +617,7 @@
 	}
 
 	// only the primary arch in the ramdisk / vendor_ramdisk / recovery partition
-	if os == Android && (module.InstallInRecovery() || module.InstallInRamdisk() || module.InstallInVendorRamdisk() || module.InstallInDebugRamdisk()) {
+	if os == Android && (module.InstallInRecovery() || module.InstallInRamdisk() || module.InstallInVendorRamdisk()) {
 		osTargets = []Target{osTargets[0]}
 	}