doc: update sun4m documentation

A few minor tidy-ups, plus add reference to the new -vga tcx and cg3 options.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

qemu-doc.texi

@@ -1996,7 +1996,7 @@ QEMU emulates the following sun4m peripherals:
 @item
 IOMMU
 @item
-TCX Frame buffer
+TCX or cgthree Frame buffer
 @item
 Lance (Am7990) Ethernet
 @item
@@ -2023,7 +2023,7 @@ firmware implementation. The goal is to implement a 100% IEEE
 
 A sample Linux 2.6 series kernel and ram disk image are available on
 the QEMU web site. There are still issues with NetBSD and OpenBSD, but
-some kernel versions work. Please note that currently Solaris kernels
+some kernel versions work. Please note that currently older Solaris kernels
 don't work probably due to interface issues between OpenBIOS and
 Solaris.
 
@@ -2035,8 +2035,9 @@ The following options are specific to the Sparc32 emulation:
 
 @item -g @var{W}x@var{H}x[x@var{DEPTH}]
 
-Set the initial TCX graphic mode. The default is 1024x768x8, currently
-the only other possible mode is 1024x768x24.
+Set the initial graphics mode. For TCX, the default is 1024x768x8 with the
+option of 1024x768x24. For cgthree, the default is 1024x768x8 with the option
+of 1152x900x8 for people who wish to use OBP.
 
 @item -prom-env @var{string}
 

qemu-options.hx

@@ -1043,7 +1043,7 @@ Rotate graphical output some deg left (only PXA LCD).
 ETEXI
 
 DEF("vga", HAS_ARG, QEMU_OPTION_vga,
-    "-vga [std|cirrus|vmware|qxl|xenfb|none]\n"
+    "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|none]\n"
     "                select video card type\n", QEMU_ARCH_ALL)
 STEXI
 @item -vga @var{type}
@@ -1068,6 +1068,14 @@ card.
 QXL paravirtual graphic card.  It is VGA compatible (including VESA
 2.0 VBE support).  Works best with qxl guest drivers installed though.
 Recommended choice when using the spice protocol.
+@item tcx
+(sun4m only) Sun TCX framebuffer. This is the default framebuffer for
+sun4m machines and offers both 8-bit and 24-bit colour depths at a
+fixed resolution of 1024x768.
+@item cg3
+(sun4m only) Sun cgthree framebuffer. This is a simple 8-bit framebuffer
+for sun4m machines available in both 1024x768 (OpenBIOS) and 1152x900 (OBP)
+resolutions aimed at people wishing to run older Solaris versions.
 @item none
 Disable VGA card.
 @end table