sec: silent wrong compiler warning in isaac

sec: silent wrong compiler warning in isaac

Silent the following compiler warning:

  bertos/sec/prng/isaac.c: In function 'isaac':
  bertos/sec/prng/isaac.c:76: warning: cast increases required alignment of target type

The warning was reported the ind() macro, that casts the first argument
(a uint32_t *) to a (uint8_t *) adds a value to it and re-casts back to
(uint32_t *).

However, the value added to the pointer is always a multiple of
uint32_t, so the warning can be suppressed without potential side
effects.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@4713 38d2e660-2303-0410-9eaa-f027e97ec537