Add proc_cmdline read permission to read_fstab

ReadDefaultFstab() calls fs_mgr_get_boot_config() which could read
/proc/bootconfig and /proc/cmdline.

Bug: 225310919
Test: TH presubmit
Change-Id: Ibe66a41d0d74d7b71dc70436af68b7a7eed721b6
2 files changed