update makefiles for adv lab according to Niclas suggestion

advanced_lab/c/Makefile

 CC = cc
-CFLAGS = -O2 -mp
+CFLAGS = -O2 -homp
 SRC = vtk_export.c shwater2d.c
 OBJS = ${SRC:.c=.o}
 DEST = shwater2d

advanced_lab/f90/Makefile

 F90 = ftn
-FFLAGS = -O2 -mp
+FFLAGS = -O2 -homp
 SRC = vtk_export.f90 shwater2d.f90
 OBJS = ${SRC:.f90=.o}
 DEST = shwater2d