MAINTAINERS: Update maintainers for ptp_vmw driver

Vivek has decided to transfer the maintainership of the VMware virtual
PTP clock driver (ptp_vmw) to Srivatsa and Deep. Update the
MAINTAINERS file to reflect this change, and also add Alexey as a
reviewer for the driver.

Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Acked-by: Vivek Thampi <vivek@vivekthampi.com>
Acked-by: Deep Shah <sdeep@vmware.com>
Acked-by: Alexey Makhalov <amakhalov@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>