I have come across many issues compiling drivers for kernel 3.8.10 builds.
The first issue "error: implicit declaration of function ā__devexit_pā [-Werror=implicit-function-declaration]"
is fixed by removal of all references to __devinit, __devexit and __devexit_p which are no longer supported in kernel 3.8.x
Along with references to __devexit_p are the parenthesis around the value passed to __devexit_p which need to be removed.
eg: on line with = __devexit_p (driver remove),
edit to: =driver remove,
Then the driver will compile (assuming no further issue to be addressed occur).
just an FYI, hope this helps build drivers for 3.8+ unless anyone has a better method?