intel: Fix pitch handling for linear blits.

intel: Fix pitch handling for linear blits.

The new assert in intelEmitCopyBlit() gets angry if we don't align to
dwords.  Rather than make the assert have a special case for height ==
1 on the assumption that the hardware doesn't use it in that case,
just supply a correct pitch.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=43214
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>