Include config.h directly if used

Include config.h directly in files that use definitions from there.
Only gmx_blas/gmx_lapack are exceptions, where the header does the
inclusion for simplicity.  There is also one of the kernel inner loop
files in nbnxn kernels that relies on the source file including
config.h.

Change-Id: Ibea7d3fafb0e7de5ee3d40e52c68fef5646edf37