savagefb: speed up the I2C bus

There is no reason to drive the savagefb I2C bus at such a low speed, so bump
it from 12.5 kbps to 50 kbps.  The Intel (i810) and Matrox framebuffer drivers
already run their I2C bus at this speed, and so are the legacy i2c-savage4 and
i2c-prosavage drivers.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
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>