enable building with mpich

Use following command to build: MPICH=1 make


[ROCm/rccl-tests commit: 86f053be84]

projects/rccl-tests/src/Makefile

@@ -44,7 +44,11 @@ endif
 ifeq ($(MPI), 1)
 HIPCUFLAGS += -DMPI_SUPPORT -I${MPI_HOME}/include
 HIPLDFLAGS += -L${MPI_HOME}/lib -lmpi
+else ifeq($(MPICH), 1)
+HIPCUFLAGS += -DMPI_SUPPORT -I/usr/include/mpich
+HIPLDFLAGS += -L/usr/lib -lmpi
 endif
+
 LIBRARIES += rccl
 HIPLDFLAGS   += $(LIBRARIES:%=-l%)