bus: mhi: core: Remove double occurrence for mhi_ctrl_ev_task() declaration

bus: mhi: core: Remove double occurrence for mhi_ctrl_ev_task() declaration

mhi_ctrl_ev_task() in the internal header file occurred twice.
Remove one of the occurrences for clean-up.

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200929175218.8178-3-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>