sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

Add support for extended descriptor format to Altera mSGDMA driver.

The format to use depends on hardware configuration (synthesis-time),
so make it compile-time kernel option.

Extended format allows DMA engine to operate with 64-bit memory addresses.

Sponsored by: DARPA, AFRL

Add driver for Altera modular Scatter-Gather DMA engine (mSGDMA).

Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D9619