cmake: do not assume ${CMAKE_GENERATOR} == make

cmake: do not assume ${CMAKE_GENERATOR} == make

* modules/BuildDPDK.cmake: always use "make"
* modules/BuildSPDK.cmake: always use "make"
  DPDK only support "make". if user wants to use other generator than
  "make", we will fail to build DPDK support. so we should always use
  "make" here. and before using "make", we need to detect it.
* cmake/modules/BuildRocksDB.cmake: use cmake for build
* src/compressor/zstd/CMakeLists.txt: use cmake for build
  just use whatever generator use specifies, and use ${CMAKE_COMMAND}
  for building the specified target, no need to repeat
  ${CMAKE_GENERATOR} for building the target.

Signed-off-by: Kefu Chai <kchai@redhat.com>