bolero: tx-macro: Fix link status not connected issue due to clk not enabled

Sometimes link status is not connected due to tx_mclk_users
not being properly updated. This is due to tx_mclk_users
enable and disable not being protected by common mutex lock.
Add mutex lock whereever it is accessed to resolve issue.

Change-Id: Ibba208be1f2d3eaf63c49e434c2ae48bc3b5b2d8
Signed-off-by: Vatsal Bucha <vbucha@codeaurora.org>