intel_gtt: Add intel_gtt from the 2D driver.

We've used it several times in bringing up the AGP driver, so it seems
useful to have aronud.

man/Makefile.am

@@ -1,6 +1,7 @@
 dist_man1_MANS = \
 	intel_gpu_dump.1 \
 	intel_gpu_top.1 \
+	intel_gtt.1 \
 	intel_reg_dumper.1 \
 	intel_reg_write.1 \
 	intel_stepping.1 \

man/intel_gtt.1

@@ -0,0 +1,14 @@
+emacs .\" shorthand for double quote that works everywhere.
+.ds q \N'34'
+.TH intel_gtt 1 "intel_gtt 1.0"
+.SH NAME
+intel_gtt \- Dump the contents of an Intel GPU's GTT
+.SH SYNOPSIS
+.B intel_gtt
+.SH DESCRIPTION
+.B intel_
+is a tool to view the contents of the GTT on an Intel GPU.  The GTT is
+the page table that maps between GPU addresses and system memory.
+This tool can be useful in debugging the Linux AGP driver
+initialization of the chip or in debugging later overwriting of the
+GTT with garbage data.