Konsole: Correct scrollUp behavior

CSI S escape sequence (SU, scroll up) ignored if number of lines to
scroll bigger than scrollable lines

REVIEW: 130133
BUG: 379318

Taken from KDE patches and adapted to TDE.

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>
(cherry picked from commit 0bb1c7eb4c)

konsole/konsole/TEScreen.cpp

@@ -825,9 +825,21 @@ void TEScreen::scrollUp(int n)
 
 void TEScreen::scrollUp(int from, int n)
 {
-  if (n <= 0 || from + n > bmargin) return;
+	if (n <= 0)
+	{
+		return;
+	}
+	if (from > bmargin)
+	{
+		return;
+	}
+	if ((from + n) > bmargin)
+	{
+		n = bmargin + 1 - from;
+	}
+
 	//FIXME: make sure `tmargin', `bmargin', `from', `n' is in bounds.
-  moveImage(loc(0,from),loc(0,from+n),loc(columns-1,bmargin));
+	moveImage(loc(0, from), loc(0, from+n), loc(columns, bmargin));
 	clearImage(loc(0, bmargin-n+1), loc(columns-1, bmargin), ' ');
 }