dsp: don't read off the end of the data array

* EQ_PARAM_CUR_PRESET will attempt to read a 32-bit value from a 16-bit
  location, resulting in an extra 16 garbage bits being read.

Change-Id: Ie6aa89c5a2d2853170cbd06343cee853a903745c
Merge pull request #3 from omnirom/android-4.4

dsp: don't read off the end of the data array