slim_ngd: Rectify define, removal messages per protocol

Populate required bits only as client handle while sending
channel define, removal messages to the master driver.
Previously, complete logical address was set as client handle
which would corrupt other fields in that byte if logical
address had non-zero MSBs. This patch fixes that problem.

Change-Id: I96e8a7917c1fe68e1c86f6837c0b9f8ee187ca3d
Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>