init.recovery: Increase tmpfs size to 350MB

When an update gets installed, gapps are backed up in tmpfs.
220MB usually aren't enough and backed up gapps get removed from RAM.
As a result, some google apps are missing after flashing the update.
We usually need to reflash gapps after each update to overcome the issue
but increasing the tmpfs size should be the proper way to fix this.

Change-Id: Ie93caba1ac30b2d3288984edbad848150224e054