automount: mount sdcard with noatime

[nicolasroche898]

# mount | grep mmc

before:
/dev/mmcblk0p1 on /mnt/mmcblk0p1 type exfat (rw,sync,relatime,fmask=0000,dmask=0000,allow_utime=0022,namecase=0,errors=remount-ro)

after:
/dev/mmcblk0p1 on /mnt/mmcblk0p1 type exfat (rw,sync,noatime,fmask=0000,dmask=0000,allow_utime=0022,namecase=0,errors=remount-ro)