ShellPkg: acpiview: Make '-h' option not require a parameter

ShellPkg: acpiview: Make '-h' option not require a parameter

Make the -h command line option a binary flag. Now, colour
highlighting is enabled whenever this flag is set (stateless),
instead of being dependent on previous acpiview command
invocations.

By removing the parameter required with the -h flag the command
line parsing logic becomes simpler.

Signed-off-by: Krzysztof Koch <krzysztof.koch@arm.com>
Reviewed-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
Reviewed-by: Zhichao Gao <zhichao.gao@intel.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>