EEPROM_AT24 depends on both I2C and SYSFS. We have in the past
added I2C 'select' statements to avoid build problems with the
first, but we still get a warning because of the second:

warning: (MACH_DAVINCI_EVM && MACH_SFFSDR && MACH_DAVINCI_DM6467_EVM && MACH_DAVINCI_DM365_EVM && MACH_DAVINCI_DA830_EVM && MACH_MITYOMAPL138 && MACH_MINI2440) selects EEPROM_AT24 which has unmet direct dependencies (I2C && SYSFS)

This removes the 'select' statements again, and forces users to
enable the driver in their configuration files, as we do for
most other drivers.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>