interconnect: Remove unused module exit code from core

interconnect: Remove unused module exit code from core

The interconnect core is currently always built in:

 menuconfig INTERCONNECT
	bool "On-Chip Interconnect management support"

So remove the module_exit function and symbolically rename module_init
to device_initcall to drive home the point.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1572546532-19248-3-git-send-email-jcrouse@codeaurora.org
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>