Update datasheet.md (#686)

Author: martab1994

content/hardware/04.pro/boards/portenta-h7/datasheets/datasheet.md

@@ -60,9 +60,9 @@ Laboratory equipment, Computer vision
       </tr>
       <tr>
          <td style="text-align: center;">Memory</td>
-         <td style="text-align: center;">8 MB / 16 MB</td>
-         <td style="text-align: center;">8 MB / 16 MB</td>
-         <td style="text-align: center;">8 MB /16 MB</td>
+         <td style="text-align: center;">8 MB SDRAM / 16 MB QSPI Flash</td>
+         <td style="text-align: center;">8 MB SDRAM / 16 MB QSPI Flash</td>
+         <td style="text-align: center;">8 MB SDRAM / 16 MB QSPI Flash</td>
       </tr>
       <tr>
          <td style="text-align: center;">Power</td>
@@ -254,12 +254,12 @@ Laboratory equipment, Computer vision
       </tr>
       <tr>
          <td rowspan="2" style="vertical-align: top;">External memories</td>
-         <td>SDRAM (optional)</td>
-         <td>Up to 64 MByte</td>
+         <td>SDRAM</td>
+         <td>8 MByte</td>
       </tr>
       <tr>
-         <td>QSPI Flash (optional)</td>
-         <td>Up to 128 MByte</td>
+         <td>QSPI Flash</td>
+         <td>16 MByte</td>
       </tr>
       <tr>
          <td rowspan="4" style="vertical-align: top;" >USB-C®</td>