Remove Kwasio (nmg) from user-selectable languages

The language had inadequate locale data, and even the name
of the Kwasio language itself was not localized to Kwasio.

Change-Id: I7b92460b7b3d736593db4a2f94d47863264561b4
Fixes: 64037672
Test: Manual (Kwasio, as 'Nmg', is no longer listed in Settings)