[radio] fix ClearSrcMatchExtEntry() Extended Address byte order (#11257)

This commit addresses an issue introduced in #10892 where the Extended
Address byte order was not properly handled when calling
`otPlatRadio` APIs. OpenThread core uses big-endian encoding for
Extended Addresses, while the `otPlatRadio` APIs expect
little-endian, as per documented behavior.

PR #10892 refactored the byte-order reversal code from
`SourceMatchController` and `LinkRaw` into the `Radio` class. While
`Radio::AddSrcMatchExtEntry()` was updated properly to reverse the
byte order, `Radio::ClearSrcMatchExtEntry()` was not. This leads to
Extended MAC addresses not being properly removed from the source
match table, potentially causing issues with indirect transmission.
This commit resolves the issue.

It is strongly recommended to cherry-pick this fix into builds that
include #10892.

src/core/radio/radio.cpp

@@ -104,6 +104,15 @@ Error Radio::AddSrcMatchExtEntry(const Mac::ExtAddress &aExtAddress)
     address.Set(aExtAddress.m8, Mac::ExtAddress::kReverseByteOrder);
     return otPlatRadioAddSrcMatchExtEntry(GetInstancePtr(), &address);
 }
+
+Error Radio::ClearSrcMatchExtEntry(const Mac::ExtAddress &aExtAddress)
+{
+    Mac::ExtAddress address;
+
+    address.Set(aExtAddress.m8, Mac::ExtAddress::kReverseByteOrder);
+    return otPlatRadioClearSrcMatchExtEntry(GetInstancePtr(), &address);
+}
+
 Error Radio::Transmit(Mac::TxFrame &aFrame)
 {
 #if (OPENTHREAD_MTD || OPENTHREAD_FTD) && OPENTHREAD_CONFIG_OTNS_ENABLE

src/core/radio/radio.hpp

@@ -1021,11 +1021,6 @@ inline Error Radio::ClearSrcMatchShortEntry(Mac::ShortAddress aShortAddress)
     return otPlatRadioClearSrcMatchShortEntry(GetInstancePtr(), aShortAddress);
 }
 
-inline Error Radio::ClearSrcMatchExtEntry(const Mac::ExtAddress &aExtAddress)
-{
-    return otPlatRadioClearSrcMatchExtEntry(GetInstancePtr(), &aExtAddress);
-}
-
 inline void Radio::ClearSrcMatchShortEntries(void) { otPlatRadioClearSrcMatchShortEntries(GetInstancePtr()); }
 
 inline void Radio::ClearSrcMatchExtEntries(void) { otPlatRadioClearSrcMatchExtEntries(GetInstancePtr()); }