The call to xilinxfb_assign is getting unwieldy when adding features
to the Xilinx framebuffer driver.  Change xilinxfb_assign() to accept
a pointer to a xilinxfb_platform_data structure to prepare for adding
additition configuration options.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: NPaul Mackerras <paulus@samba.org>