Do not allow access to device:chr_file for system

Also labels /dev/mpu and /dev/mpuirq as gps device.
mpu is motion processing unit and is resposible for
gyroscope functionality.

Change-Id: If7f1a5752c550b72fac681566e1052f09e139ff0

file_contexts

@@ -55,6 +55,8 @@
 /dev/log(/.*)?		u:object_r:log_device:s0
 /dev/mem		u:object_r:kmem_device:s0
 /dev/modem.*		u:object_r:radio_device:s0
+/dev/mpu		u:object_r:gps_device:s0
+/dev/mpuirq		u:object_r:gps_device:s0
 /dev/mtd(/.*)?		u:object_r:mtd_device:s0
 /dev/mtd/mtd5		u:object_r:radio_device:s0
 /dev/mtd/mtd5ro		u:object_r:radio_device:s0

system.te

@@ -143,7 +143,6 @@ allow system sysfs_nfc_power_writable:file rw_file_perms;
 
 # Access devices.
 allow system device:dir r_dir_perms;
-allow system device:chr_file rw_file_perms;
 allow system device:sock_file rw_file_perms;
 allow system akm_device:chr_file rw_file_perms;
 allow system accelerometer_device:chr_file rw_file_perms;