ti-ipc-rtos: Remove M4F target for omap-a15
ti-ipc-rtos: Remove M4F target for omap-a15

- M4F target is not needed for omap-a15
- This reduces build time for platform associated with omap-a15

Signed-off-by: Sam Nelson <922b89dc606ff5f34a79f0527810322597be4ea8@ti.com>
Signed-off-by: Denys Dmytriyenko <d29de71aea38aad3a87d486929cb0aad173ae612@ti.com>

rcn-ee/meta-ti,rcn-ee/meta-ti,rcn-ee/meta-ti,rcn-ee/meta-ti