mlx5: stop including <asm-generic/kmap_types.h>

<linux/highmem.h> is the placace the get the kmap type flags, asm-generic
files are generic implementations only to be used by architecture code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>