coresight: remove request for memory reservation using export_compat

The TMC driver now uses dma_alloc_coherent api to allocate contiguous
memory instead of allocate_contiguous_ebi when configured for ETR. This
eliminates the need for EXPORT_COMPAT support in the TMC driver.

Change-Id: I79550d2ff490c02329e4b860b8aa8816d4890d50
Signed-off-by: Aparna Das <adas@codeaurora.org>