[PATCH] ioc4: CONFIG split

The SGI IOC4 I/O controller chip drivers are currently all configured by
CONFIG_BLK_DEV_SGIIOC4.  This is undesirable as not all IOC4 hardware features
are needed by all systems.

This patch adds two configuration variables, CONFIG_SGI_IOC4 for core IOC4
driver support (see patch 1/3 in this series for further explanation) and
CONFIG_SERIAL_SGI_IOC4 to independently enable serial port support.

Signed-off-by: Brent Casavant <bcasavan@sgi.com>
Acked-by: Pat Gefre <pfg@sgi.com>
Acked-by: Jeremy Higdon <jeremy@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>