ENGR00153275-1 ahci L2638 add the standalone ahci temperature monitor

ENGR00153275-1 ahci L2638 add the standalone ahci temperature monitor

based on the 2.6.38 kernel mainline, refer to linux lm-sensors
architeture, add the standalone ahci temperature monitor driver
on fsl i.mx53 platforms.
Less than half sencond is used in one temperature read operation.

usage:
Use the following cmd to cat the i.mx53 soc temperature after
boot up i.mx53 system in user space.
for example:
...$ cat /sys/class/hwmon/hwmon1/device/temp1_input
61000
or run the following cmd after configure the lm-sensors
...$ sensors
imx-ahci-hwmon-isa-0000
Adapter: ISA adapter
temp1:        +58.0 C

Signed-off-by: Richard Zhu <r65037@freescale.com>