tdfxfb: fix section mismatch warnings

tdfxfb: fix section mismatch warnings

tdfxfb_setup() can be __init.  This fixes the modpost section mismatch
warnings:

WARNING: vmlinux.o(.text+0x4cff9b): Section mismatch: reference to .init.data:mode_option (between 'tdfxfb_setup' and 'getclkMHz')
WARNING: vmlinux.o(.text+0x4cffa8): Section mismatch: reference to .init.data: (between 'tdfxfb_setup' and 'getclkMHz')

[krzysztof.h1@poczta.fm: use __init, not __devinit]
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>