CMSIS-DSP: Fix FIR document
Samples in the state buffer are stored in the following order.
@par
<pre>
- {x[n-numTaps+1], x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2]....x[0], x[1], ..., x[blockSize-1]}
+ {x[n-numTaps+1], x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2]....x[n](==pSrc[0]), x[n+1](==pSrc[1]), ..., x[n+blockSize-1](==pSrc[blockSize-1])}
</pre>
@par
Note that the length of the state buffer exceeds the length of the coefficient array by <code>blockSize-1</code>.
