Add RoundUpToMultiple and DivideAndRoundUp functions to MathUtils.h (#6989)

* Add RoundUpToMultiple and DivideAndRoundUp functions to MathUtils.h

Signed-off-by: Tommy Walton <waltont@amazon.com>

* Rename DivideByMultiple2 back to DivideByMultiple, now that I've confirmed it's not in use in the codebase. RHI::DivideByMultiple can be fully deprecated in favor of AZ::DivideAndRoundUp at a later date, once the deprecation strategy has been finalized.

Signed-off-by: Tommy Walton <waltont@amazon.com>

* Update based on PR feedback

Signed-off-by: Tommy Walton <waltont@amazon.com>

* Switched from std::numeric_limits to AZStd::numeric_limits and updated the header to indicate it works for non-power of two alignments, but that SizeAlignUp is more efficient if the alignment is a power of 2

Signed-off-by: Tommy Walton <waltont@amazon.com>

* Added missing arguments to the assert, and a missing namespace and include that failed to compile on non-unity builds

Signed-off-by: Tommy Walton <waltont@amazon.com>

Code/Framework/AzNetworking/AzNetworking/UdpTransport/UdpNetworkInterface.cpp

@@ -17,6 +17,7 @@
 #include <AzNetworking/Utilities/NetworkCommon.h>
 #include <AzCore/Console/IConsole.h>
 #include <AzCore/Console/ILogger.h>
+#include <AzCore/Math/MathUtils.h>
 
 namespace AzNetworking
 {
@@ -539,7 +540,7 @@ namespace AzNetworking
             // Each fragmented packet we send adds an extra fragmented packet header, need to deduct that from our chunk size, otherwise we infinitely loop
             // SSL encryption can also inflate our payload so we pre-emptively deduct an estimated tax
             const uint32_t chunkSize = connection.GetConnectionMtu() - net_FragmentedHeaderOverhead - net_SslInflationOverhead;
-            const uint32_t numChunks = (packetSize + chunkSize - 1) / chunkSize; // We want to round up on the remainder
+            const uint32_t numChunks = AZ::DivideAndRoundUp(packetSize, chunkSize); // We want to round up on the remainder
             const uint8_t* chunkStart = packetData;
             const SequenceId fragmentedSequence = connection.m_fragmentQueue.GetNextFragmentedSequenceId();
             uint32_t bytesRemaining = packetSize;