doc: fix broken references

There are numerous broken references to Documentation files (in other
Documentation files, in comments, etc.). These broken references are
caused by typo's in the references, and by renames or removals of the
Documentation files. Some broken references are simply odd.

Fix these broken references, sometimes by dropping the irrelevant text
they were part of.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Documentation/spi/pxa2xx

@@ -2,7 +2,7 @@ PXA2xx SPI on SSP driver HOWTO
 ===================================================
 This a mini howto on the pxa2xx_spi driver.  The driver turns a PXA2xx
 synchronous serial port into a SPI master controller
-(see Documentation/spi/spi_summary). The driver has the following features
+(see Documentation/spi/spi-summary). The driver has the following features
 
 - Support for any PXA2xx SSP
 - SSP PIO and SSP DMA data transfers.
@@ -85,7 +85,7 @@ Declaring Slave Devices
 -----------------------
 Typically each SPI slave (chip) is defined in the arch/.../mach-*/board-*.c
 using the "spi_board_info" structure found in "linux/spi/spi.h". See
-"Documentation/spi/spi_summary" for additional information.
+"Documentation/spi/spi-summary" for additional information.
 
 Each slave device attached to the PXA must provide slave specific configuration
 information via the structure "pxa2xx_spi_chip" found in