kernel: i2c padconf workaround

The padconf library runs in user mode, but to actually affect the
padconf register contents, the processor has to be in privileged
mode. A full server based solution will be developed, but for now
just set the pinmux in the kernel at boot.

Change-Id: Id27c21c4b2126f4ea8b68172237a213b0f4bfd19
i2c: initial bus drivers for am335x and dm37xx

Change-Id: Ia4bebbef1d7a2da570504f3dc25ae5bd3b5c7c25
Importing usr.sbin/i2cscan

Change-Id: I905263b6b51410455513f4eeeffa019f599e5431
libi2cdriver: library for i2c device drivers

Change-Id: I7af536278e91cd33ee43cb683d46f5cb8d0786fe
cat24c256: driver for the cat24c256 i2c eeprom

Change-Id: Ia50823dc2f8ece2abf8a5fae30488682dbcd556b
eepromread: simple program to view eeprom contents

This program uses the i2c /dev interface to read the
contents of EEPROMs and display it to the user in
HEX and ASCII. It also has a mode that can display
data in label:value pairs. That mode is used for
board detection in the rc script to start the right
i2c drivers for the board.

Change-Id: I9bcae6d34d38ddb0629408a9be543a699d7fab35