qt4-webos: Inherit webos_enhanced_submissions

:Release Notes:
Drop inherits already included in .inc file, change
webos_submissions to webos_enhanced_submissions.

:Detailed Notes:
Tags are matching enhanced conventions, so we can inherit
webos_enhanced_submissions now.

:Testing Performed:
Only build tested.

:QA Notes:
No change in image.

:Issues Addressed:
[GF-5328] Improve build performance and allow to build completely from PREMIRROR
[GF-12492] Convert PREFERRED_VERSION to WEBOS_VERSION and modify webos_enhanced_submissions.bbclass

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: Ib5308a7bf55bdbf451991bd3671930789e0fef67
Reviewed-on: https://g2g.palm.com/3067
Reviewed-by: Build Verification
Reviewed-by: Susan Montooth <susan.montooth@lge.com>
Tested-by: Susan Montooth <susan.montooth@lge.com>