tty: vt: remove checks for count in consw::con_clear() implementations

tty: vt: remove checks for count in consw::con_clear() implementations

'count' in consw::con_clear() is guaranteed to be positive. csi_X() (the
only caller) takes the minimum of the vc parameter (which is at least 1)
and count of characters till the end of the line. The latter is computed
as a subtraction of vc->vc_cols (count) and vc->state.x (offset). So for
the worst case, full line, it is 1.

Therefore, there is no point in checking zero or negative values (width
is now unsigned anyway).

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-parisc@vger.kernel.org
Tested-by: Helge Deller <deller@gmx.de> # parisc STI console
Link: https://lore.kernel.org/r/20240122110401.7289-23-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>