ShellPkg/AcpiView: Update print-formatter prototype

As of now, the print-formatter implemented by the FNPTR_PRINT_FORMATTER
function pointer takes two parameters, the format string and the pointer
to the field. For cases where the print-formatter has to have access to
the length of the field, there is no clean way to currently do it. In
order to resolve this, update the print-formatter's prototype to take
the length of the field as a third parameter. This change should improve
the overall robustness and flexibility of AcpiView.

Signed-off-by: Rohit Mathew <Rohit.Mathew@arm.com>
Change-Id: I28a007f15bbaa3ced0f96f5c39a17b77a9ad6d7e
Cc: James Morse <james.Morse@arm.com>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Cc: Thomas Abraham <thomas.abraham@arm.com>
Cc: Zhichao Gao <zhichao.gao@intel.com>