Auto generate recovery partition

This change conditionally auto generates the recovery partition in
filesystem_generator.

Test: m soong_generated_recovery_filesystem_test
Bug: 381888358
Change-Id: I8938e842d8587ec1c986542385ed50c19dc1c76d
diff --git a/fsgen/fsgen_mutators.go b/fsgen/fsgen_mutators.go
index 0cc643e..b99e2da 100644
--- a/fsgen/fsgen_mutators.go
+++ b/fsgen/fsgen_mutators.go
@@ -150,6 +150,7 @@
 				},
 				"ramdisk":        {},
 				"vendor_ramdisk": {},
+				"recovery":       {},
 			},
 			fsDepsMutex:                     sync.Mutex{},
 			moduleToInstallationProps:       map[string]installationProperties{},