Enable verbose output during VPP cmake compiling

Enable verbose output during VPP cmake compiling

During VPP compiling, the command “make build-release V=1” gives verbose output on dpdk part.
This is to enable verbose output on vpp part, with CMAKE_VERBOSE_MAKEFILE:BOOL=ON passed to cmake.
It would help to get more cmake compiling information.

Change-Id: I2b01c8e234beb3189fe401801ff339f224c14470
Signed-off-by: Lijian Zhang <Lijian.Zhang@arm.com>
Reviewed-by: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
Reviewed-by: Sirshak Das <Sirshak.Das@arm.com>