vt: ignore csi sequences with intermediate characters.
Various csi sequences contain intermediate characters between the
parameters and the final character. Introduce a additional state that
cleanly ignores these sequences.
This allows the vt to ignore these sequences used by more capable
terminal implementations such as "request mode", etc.
Signed-off-by: Martin Hostettler <textshell@uchuujin.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>