Fix reading marchid and mimpid

It seems to have been a copy-paste error.
We ran into a very nasty bug in oreboot on the Allwinner D1 (C906) where
an errata patch in Linux relies on those two being zero.

Signed-off-by: Daniel Maslowski <info@orangecms.org>

src/register/marchid.rs

@@ -16,7 +16,7 @@ impl Marchid {
     }
 }
 
-read_csr!(0xF11);
+read_csr!(0xF12);
 
 /// Reads the CSR
 #[inline]

src/register/mimpid.rs

@@ -16,7 +16,7 @@ impl Mimpid {
     }
 }
 
-read_csr!(0xF11);
+read_csr!(0xF13);
 
 /// Reads the CSR
 #[inline]