xkeyboard-config: Remove xkbcomp from RDEPENDS

:Release Notes:
xkbcomp isn't available in Open webOS, because it's also built without
x11 in DISTRO_FEATURES

:Detailed Notes:

:Testing Performed:
No change in build

:QA Notes:
No change in image

:Issues Addressed:
[ES-118] Evaluate possibility to build everything available in verification jobs

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: Iaec899e61f7d7fd4197def317a0c725f1c35b865
Reviewed-on: https://g2g.palm.com/2790
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Tested-by: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Herb Kuta <herb.kuta@lge.com>
Reviewed-by: Build Verification
Reviewed-by: Susan Montooth <susan.montooth@lge.com>