About phone: update memory description

When this change was introduced,
https://github.com/SaberMod/android_packages_apps_Settings/commit/185ec4f4a2a3bb3e46f4bb8d37bffa22db7a11c8
the previously used method of showing available free memory was removed
and now shows the memory total instead.  Users may get confused about
what is being displayed for their device memory, especially when upgrading
from a older version of android in ROMs or new devices.

Patch set 1:  https://github.com/SaberMod/android_packages_apps_Settings/commit/6318775a76d4949ab2a14dba273ca9b71159b603
Patch set 2:  Switch string to "Memory total". Update commit message.
Patch set 3:  Fix small typo in commit message.

Signed-off-by: Paul Beeler <sparksco@gmail.com>