misc: eeprom_93xx46: Remove hardcoded bit lengths

misc: eeprom_93xx46: Remove hardcoded bit lengths

This avoids using magic numbers based on the length of an address or a
command, while we only want to differentiate between 8-bit and 16-bit.

The driver was previously wrapping around the offset in the write
operation, this now returns -EINVAL instead (but should never happen in
the first place).

If two pointer indirections are too many, we could move the flags to the
main struct instead, but I doubt it’s going to make any sensible
difference on any hardware.

Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
Link: https://lore.kernel.org/r/20210511210727.24895-2-linkmauve@linkmauve.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>