android/: Rename Plat->SystemExt*SepolicyDirs

Align with changes in system/sepolicy and build/make.

Signed-off-by: Felix <google@ix5.org>
Change-Id: I326962648a78e68e8cc83fdc22d8274eaecb8c8c
diff --git a/android/config.go b/android/config.go
index ee31c10..d81e7db 100644
--- a/android/config.go
+++ b/android/config.go
@@ -1064,12 +1064,12 @@
 	return c.config.productVariables.BoardOdmSepolicyDirs
 }
 
-func (c *deviceConfig) PlatPublicSepolicyDirs() []string {
-	return c.config.productVariables.BoardPlatPublicSepolicyDirs
+func (c *deviceConfig) SystemExtPublicSepolicyDirs() []string {
+	return c.config.productVariables.SystemExtPublicSepolicyDirs
 }
 
-func (c *deviceConfig) PlatPrivateSepolicyDirs() []string {
-	return c.config.productVariables.BoardPlatPrivateSepolicyDirs
+func (c *deviceConfig) SystemExtPrivateSepolicyDirs() []string {
+	return c.config.productVariables.SystemExtPrivateSepolicyDirs
 }
 
 func (c *deviceConfig) SepolicyM4Defs() []string {