layer.conf: prepend instead of append to sort before oe-core in BBPATH
layer.conf: prepend instead of append to sort before oe-core in BBPATH

This helps avoid bblayers.conf ordering issues, when temporarily overriding
files from oe-core in meta-ti.

Signed-off-by: Denys Dmytriyenko <d29de71aea38aad3a87d486929cb0aad173ae612@ti.com>

tylerwhall/meta-ti,jumpnow/meta-ti,smoosvi/Test4,RedFIR/meta-ti,joelagnel/meta-ti,RedFIR/meta-ti,tylerwhall/meta-ti,joelagnel/meta-ti,tylerwhall/meta-ti,rcn-ee/meta-ti,joelagnel/meta-ti,tylerwhall/meta-ti,joelagnel/meta-ti,jumpnow/meta-ti,RedFIR/meta-ti,rcn-ee/meta-ti,rcn-ee/meta-ti,smoosvi/Test4,RedFIR/meta-ti,rcn-ee/meta-ti