[PERF]: Do not declare the PCR in KeGetPcr as volatile. It is only volatile as in...

[PERF]: Do not declare the PCR in KeGetPcr as volatile. It is only volatile as in "if there is a context switch, the PCR is different". You are in a LOT of trouble if the thread switches while your code is running in the first place, and your code is somehow running as a different thread!
This change makes C code a lot neater, especially during PCR access, because it doesn't force reloading the PCR each time. For example, Read-Modify-Operations on the PCR, such as AND are 1 line of assembly instead of 3.
This helps and will help further with the C HAL, as well as the C trap handlers.

svn path=/trunk/; revision=45210