i3c: dw: Fix dw_i3c_master_disable controller by using correct mask

The controller was being disabled incorrectly. The correct way is to clear
the DEV_CTRL_ENABLE bit.

Fix this by clearing this bit.

Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: <stable@vger.kernel.org>
Fixes: 1dd728f5 ("i3c: master: Add driver for Synopsys DesignWare IP")
Signed-off-by: Vitor Soares <vitor.soares@synopsys.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>