drm/mgag200: Rename struct i2c_algo_bit_data callbacks

Align the names of the algo-bit helpers with mgag200's convention of
using an mgag200 prefix plus the struct's name plus the callback's name
for such function symbols.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513125620.6337-9-tzimmermann@suse.de