Add several missing messages from SPI3, SPI4 and SPI5:
 - Terminate Process
 - Continue Task
 - Target Transfer Disable
 - Clear ACA
 - LUN Reset
 - ACA
 - QAS Request
Rename some older commands to their SPI5 names:
 - Command Complete -> Task Complete
 - Abort -> Abort Task Set
 - Bus device Reset -> Target Reset
 - Clear Queue -> Clear Task Set

Change spi_print_msg() to always consume one byte, even if we don't
recognise it.  That allows drivers to call it in a loop to print all
messages.
Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>