fbdev: atafb - Fix line length handling

  - Make sure par->next_line is always set (this was done for Falcon only),
    as all the text console drawing operations need a valid par->next_line,
  - Make sure fix->line_length is always set, as some userspace applications
    need it because they don't have fallback code for the case where it's zero.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
diff --git a/drivers/video/atafb.c b/drivers/video/atafb.c
index 77eb8b3..b7646ad 100644
--- a/drivers/video/atafb.c
+++ b/drivers/video/atafb.c
@@ -614,7 +614,7 @@
 	fix->xpanstep = 0;
 	fix->ypanstep = 1;
 	fix->ywrapstep = 0;
-	fix->line_length = 0;
+	fix->line_length = par->next_line;
 	fix->accel = FB_ACCEL_ATARIBLITT;
 	return 0;
 }
@@ -691,6 +691,7 @@
 		return -EINVAL;
 	par->yres_virtual = yres_virtual;
 	par->screen_base = screen_base + var->yoffset * linelen;
+	par->next_line = linelen;
 	return 0;
 }
 
@@ -918,7 +919,7 @@
 		fix->visual = FB_VISUAL_TRUECOLOR;
 		fix->xpanstep = 2;
 	}
-	fix->line_length = 0;
+	fix->line_length = par->next_line;
 	fix->accel = FB_ACCEL_ATARIBLITT;
 	return 0;
 }
@@ -1852,7 +1853,7 @@
 		fix->ypanstep = 0;
 	}
 	fix->ywrapstep = 0;
-	fix->line_length = 0;
+	fix->line_length = par->next_line;
 	fix->accel = FB_ACCEL_ATARIBLITT;
 	return 0;
 }
@@ -1910,6 +1911,7 @@
 		return -EINVAL;
 	par->yres_virtual = yres_virtual;
 	par->screen_base = screen_base + var->yoffset * linelen;
+	par->next_line = linelen;
 	return 0;
 }
 
@@ -2169,7 +2171,7 @@
 	fix->xpanstep = 0;
 	fix->ypanstep = 0;
 	fix->ywrapstep = 0;
-	fix->line_length = 0;
+	fix->line_length = par->next_line;
 	return 0;
 }
 
@@ -2184,6 +2186,8 @@
 	    var->xoffset > 0 ||
 	    var->yoffset > 0)
 		return -EINVAL;
+
+	par->next_line = external_xres_virtual * external_depth / 8;
 	return 0;
 }