patch for zr364xx driver

[xyzzy at speakeasy.org (Trent Piepho)]

There zr364xx driver sometimes needs to byteswap a buffer.  The kernel has
functions to do this, and some arches have optimized asm code written for
it, or at least C code that compiles well.  This patch uses one of those
functions.

Also, gcc sometimes thinks pointer aliasing may occur when it won't.  In a
loop like:

if(i=0;i<BUFFER_SIZE/2;i++) swab16s((u16*)cam->buffer + i);

gcc thinks that the value of the pointer cam->buffer may change, i.e. that
somehow &(cam->buffer) == &(cam->buffer[i]).  So on every iteration of the
loop it re-loads the buffer pointer out of the cam struct.  If you use a
temp variable to hold the pointer:

u16 *buf = (u16*)cam->buffer;
if(i=0;i<BUFFER_SIZE/2;i++) swab16s(buf + i);

gcc knows that &(buf) != &(buf[i]), since the address of buf is never
taken, so gcc doesn't need to re-load buf each iteration.

Anyway, here is the patch:
http://linuxtv.org/hg/~tap/v4l-dvb?cmd=changeset;node=6b208a1d566c;style=gitweb

Antoine, does it look ok?