parport_pc needs dma-mapping.h

alpha:

drivers/parport/parport_pc.c: In function 'parport_pc_fifo_write_block_dma':
drivers/parport/parport_pc.c:636: warning: implicit declaration of function 'dma_map_single'
drivers/parport/parport_pc.c:637: error: 'DMA_TO_DEVICE' undeclared (first use in this function)
drivers/parport/parport_pc.c:637: error: (Each undeclared identifier is reported only once
drivers/parport/parport_pc.c:637: error: for each function it appears in.)

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>