fbdev: pxafb: Fix multiple clamped values in pxafb_adjust_timing

fbdev: pxafb: Fix multiple clamped values in pxafb_adjust_timing

commit 0155e868cbc111846cc2809c1546ea53810a56ae upstream.

The variables were never clamped because the return value of clamp_val()
was not used. Fix this by assigning the clamped values, and use clamp()
instead of clamp_val().

Cc: stable@vger.kernel.org
Fixes: 3f16ff608a75 ("[ARM] pxafb: cleanup of the timing checking code")
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>