Revisit sane inode numbers for ext4/f2fs for large capacity like 512GB

In the 512GB case, F2FS gives much less # of free inodes as we expected due to
filesystem metadata format. In order to provide more, there is an option "-i"
in mkfs.f2fs, but in Android, that is just overkill to use, since we already
have 11,661,194.

Bug: 111969865
Change-Id: Ifca6ae1864fd704116bf622954949ab6c2e00f5d
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>