ShellPkg: acpiview: SLIT: Validate System Locality count

ShellPkg: acpiview: SLIT: Validate System Locality count

1. Check if the 'Number of System Localities' provided can be
represented in the SLIT table. The table 'Length' field is a 32-bit
value while the 'Number of System Localities' field is 64-bit long.

2. Check if the SLIT matrix fits in the table buffer. If N is the SLIT
locality count, then the matrix used to represent the localities is
N*N bytes long. The ACPI table length must be big enough to fit the
matrix.

3. Remove (now) redundant 64x64 bit multiplication.

Signed-off-by: Krzysztof Koch <krzysztof.koch@arm.com>