[CIFS] Remove redundant NULL check

Noticed by Coverity checker.
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifssmb.c

@@ -2159,7 +2159,6 @@ copyRetry:
 		cFYI(1, ("Send error in copy = %d with %d files copied",
 			rc, le16_to_cpu(pSMBr->CopyCount)));
 	}
-	if (pSMB)
 	cifs_buf_release(pSMB);
 
 	if (rc == -EAGAIN)
@@ -2249,7 +2248,6 @@ createSymLinkRetry:
 	if (rc)
 		cFYI(1, ("Send error in SetPathInfo create symlink = %d", rc));
 
-	if (pSMB)
 	cifs_buf_release(pSMB);
 
 	if (rc == -EAGAIN)
@@ -4095,7 +4093,6 @@ getDFSRetry:
 				 target_nodes, nls_codepage);
 
 GetDFSRefExit:
-	if (pSMB)
 	cifs_buf_release(pSMB);
 
 	if (rc == -EAGAIN)
@@ -5117,7 +5114,6 @@ setPermsRetry:
 	if (rc)
 		cFYI(1, ("SetPathInfo (perms) returned %d", rc));
 
-	if (pSMB)
 	cifs_buf_release(pSMB);
 	if (rc == -EAGAIN)
 		goto setPermsRetry;
@@ -5340,7 +5336,6 @@ QAllEAsRetry:
 			}
 		}
 	}
-	if (pSMB)
 	cifs_buf_release(pSMB);
 	if (rc == -EAGAIN)
 		goto QAllEAsRetry;
@@ -5490,7 +5485,6 @@ QEARetry:
 			}
 		}
 	}
-	if (pSMB)
 	cifs_buf_release(pSMB);
 	if (rc == -EAGAIN)
 		goto QEARetry;