staging/xgifb: Use sis headers and remove duplicated structs and defines

[Peter Huewe]

Since the xgifb driver used the sis driver as a template for development,
a lot of defines and structs were redefined with only slightly different names.
This patchset tries to remove some of these duplicates by including the sis headers
and replacing any xgi struct/define by its identical twin from the sis headers.

The patches should not change any behavior of the driver, with the possible
exception of patch [PATCH 1/4] staging/xgifb: Remove unsupported mode LCD_320x480

Signed-off-by: Peter Huewe <peterhuewe at gmx.de>

git diff --stat origin
drivers/staging/xgifb/XGI_main.h    |   78 ++++------------------------
drivers/staging/xgifb/XGI_main_26.c |   95 ++++++++++++++++++-----------------
drivers/staging/xgifb/XGIfb.h       |    2 +-
drivers/staging/xgifb/vb_init.c     |    2 +-
drivers/staging/xgifb/vb_setmode.c  |   22 ++++----
drivers/staging/xgifb/vb_struct.h   |   79 +++--------------------------
drivers/staging/xgifb/vb_table.h    |   10 ++--
drivers/staging/xgifb/vgatypes.h    |    9 +++
8 files changed, 94 insertions(+), 203 deletions(-)