ARM: dts: msm: remove contiguous etr memory reservation support for 8084

The TMC driver now uses dma_alloc_coherent api to allocate contiguous
memory instead of allocate_contiguous_ebi when configured for ETR.
This eliminates need to specify EBI memory reservation requirement,
remove the same from dt.

Change-Id: I34284d9eeb7e68a9f1004ef998f531c7f3b82815
Signed-off-by: Aparna Das <adas@codeaurora.org>