i2c-msm-v2: teardown BAM pipes before turning off clocks

Tearing down BAM pipe causes accessing of BAM registers
(indirectly by the BAM driver). Register access in turn
requires clocking to the internal bus. Lack of clocking
may result in a crash.

Change-Id: I692e83ea38cafe34f4c9f34dda3010d57c200237
Signed-off-by: Sana Venkat Raju <c_vsana@codeaurora.org>