sysfs_create_group() races with userspace. Use dev_groups instead which
prevents all the problems of sysfs_create_group().

Fixes: a1944676 ("misc: keba: Add basic KEBA CP500 system FPGA support")
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Gerhard Engleder <eg@keba.com>
Link: https://lore.kernel.org/r/20240819192645.50171-1-gerhard@engleder-embedded.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>