spi_s3c24xx: add FIQ pseudo-DMA support

Add pseudo-DMA by FIQ to the S3C24XX SPI driver.  This allows the driver
to get DMA-like performance where there are either no free DMA channels or
when doing transfers that required both TX and RX data paths.

Since this patch requires the addition of an assembly file to hold the FIQ
code, we rename the module (instead of adding a rename of the .c file to
this patch).  We expect most users are loading this via udev and thus
there should be no change to the userland configuration.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Simtec Linux Team <linux@simtec.co.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>