diag: Add sysfs parameter to control diag mask clear

This patch adds syfs parameter which controls clearing
of the peripheral masks upon USB disconnect and stopping
ODL.
This patch takes proper care for handling buffers
while clearing masks.

CRs-Fixed: 1081142
Change-Id: Ibe070661618258513d683bfec13ff10f23bee5d6
Signed-off-by: Manoj Prabhu B <bmanoj@codeaurora.org>