Remove bcprov from Maven Central from target platform

There are IP issues with parts of bcprov
https://gitlab.eclipse.org/eclipsefdn/emo-team/iplab/-/issues/3008#note_1020135
therefore be explicit to not consume the bcprov from Maven Central

For now the Maven central one wasn't ending up in the p2 output, so
AFAICT this makes no difference to what is published.

eclipse.platform.releng.prereqs.sdk/eclipse-sdk-prereqs.target

@@ -48,9 +48,8 @@
       <unit id="javax.xml" version="1.4.1.v20220503-2331"/>
 
       <!-- PGP - See bug 570907 -->
-      <!-- Currently sticking to Orbit as upstream is jarsigned by a not rooted cert -->
-      <!-- We may remove it and use upstream from Central when we can have PGP signture
-        used for trust despite the jarsignature -->
+      <!-- Currently sticking to Orbit as we cannot consume bcprov direct from Maven because of IP
+           issues, see https://gitlab.eclipse.org/eclipsefdn/emo-team/iplab/-/issues/3008#note_1020135 -->
       <unit id="org.bouncycastle.bcpg" version="1.71.0.v20220723-1943"/>
       <unit id="org.bouncycastle.bcprov" version="1.71.0.v20220723-1943"/>
 
@@ -228,16 +227,6 @@
 					<artifactId>commons-lang</artifactId>
 					<version>2.6</version>
 				</dependency>
-				<dependency>
-					<groupId>org.bouncycastle</groupId>
-					<artifactId>bcpg-jdk18on</artifactId>
-					<version>1.71</version>
-				</dependency>
-				<dependency>
-					<groupId>org.bouncycastle</groupId>
-					<artifactId>bcprov-jdk18on</artifactId>
-					<version>1.71</version>
-				</dependency>
 				<dependency>
 					<groupId>commons-io</groupId>
 					<artifactId>commons-io</artifactId>