Set Read Ahead to 512k by default

Change-Id: I7b24c133b5470b0f4d9108a2a2025a3426c0d65e
Signed-off-by: Josue Rivera <prbassplayer@gmail.com>
slim.mk: Reorganize makefile to fix incorrect dataroaming flag

Calling subsequent .mk files in a wrong order caused the dataroaming flag being set incorrectly.

Layout matched with Hammerhead one atm.

Change-Id: I64666420f3f77b789acf5fecbf5a45e3310f838c
Merge remote-tracking branch 'slim/kk4.4' into kk44s