eeprom: More consistent symbol names

Now that all EEPROM drivers live in the same place, let's harmonize
their symbol names.

Also fix eeprom's dependencies, it definitely needs sysfs, and is no
longer experimental after many years in the kernel tree.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>