secure-boot-v2: fix minor typo (s/MFG1/MGF1)

docs/en/security/secure-boot-v2.rst

@@ -150,7 +150,7 @@ The content of each signature block is shown in the following table:
           - Pre-calculated M’, derived from ‘n’
         * - 812
           - 384
-          - RSA-PSS Signature result (section 8.1.1 of RFC8017) of image content, computed using following PSS parameters: SHA256 hash, MFG1 function, salt length 32 bytes, default trailer field (0xBC).
+          - RSA-PSS Signature result (section 8.1.1 of RFC8017) of image content, computed using following PSS parameters: SHA256 hash, MGF1 function, salt length 32 bytes, default trailer field (0xBC).
         * - 1196
           - 4
           - CRC32 of the preceding 1196 bytes.