buildroot: increase net.core.rmem_max

This defines the max socket receive buffer size. Goes together with
go/fibercl/83529.

Change-Id: I7de601d67da5f93bd2bdadf3d1f3c94e2e28d989
diff --git a/fs/skeleton/etc/init.d/S01sysctl.platform_gfibertv b/fs/skeleton/etc/init.d/S01sysctl.platform_gfibertv
index 5cd3608..0b9a316 100755
--- a/fs/skeleton/etc/init.d/S01sysctl.platform_gfibertv
+++ b/fs/skeleton/etc/init.d/S01sysctl.platform_gfibertv
@@ -6,7 +6,7 @@
     # Avoid UDP packet loss by increasing socket buffer size.
     # rmem_max defines the maximum receive socket buffer size in bytes.
     # The actual buffer size is set in sagesrv.
-    sysctl net.core.rmem_max=4194304
+    sysctl net.core.rmem_max=5242880
     # Set the socket write buffer size large enough to hold a complete
     # blocksize from the streamer.
     # wmem_max defines the maximum send socket buffer size in bytes.