bridgingcommands:Move ClearMessageFlags to new API

Rewrite ipmiAppClearMessageFlags command to use the newly
introduced IPMI provider API.

Tested:
Verified using ipmitool ClearMessageFlags behavior is same
before and after the changes.

Command : ipmitool raw 0x06 0x31 //Get Message Flags
Response: 02

Command : ipmitool raw 0x06 0x30 0x00 //Clear Message Flags
Response:

Signed-off-by: jayaprakash Mutyala <mutyalax.jayaprakash@intel.com>
Change-Id: I8c03050332408e909ab61994f337cfa2c1c036a4
2 files changed