[true-hitless] fix eMMC log

Correct mount point check, with true hitless package there will be 2
lines with the path thus emmc-log will fail to start.

Tested: Mount point check passed on a system with true hitless

Fusion-Link: https://fusion2.corp.google.com/e3e58ace-c514-3c3b-aaad-c4a5af93e9e5
Google-Bug-Id: 467359892
Change-Id: If39e86411d6dfd8b6f086d4820a9efbb613a2742
Signed-off-by: Yuxiao Zhang <yuxiaozhang@google.com>
diff --git a/meta-gbmc-staging b/meta-gbmc-staging
index 492dbef..e393ac2 160000
--- a/meta-gbmc-staging
+++ b/meta-gbmc-staging
@@ -1 +1 @@
-Subproject commit 492dbef718bf4212afbb353c96c4d32c08e2adc3
+Subproject commit e393ac256dfd42f40e239d63b8716fff2819b42b