ARM: pxa: Minor naming fixes in spitz.c

The NAND init section was erroneously named "Framebuffer".
Gpio expander section should really be called "I2C devices"
since it contains all i2c init code.

Signed-off-by: Marko Katic <dromede@gmail.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com>