Documentation: x86: Fix a typo in fsgs.rst

Fix a spelling typo in fsgs.rst.

Signed-off-by: Adrian Bütler <buetlera123@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20250426122303.15905-1-buetlera123@gmail.com>

Author: Adrian Bütler

Documentation/arch/x86/x86_64/fsgs.rst

@@ -130,7 +130,7 @@ instructions. Clang 5 supports them as well.
 
   =================== ===========================
   _readfsbase_u64()   Read the FS base register
-  _readfsbase_u64()   Read the GS base register
+  _readgsbase_u64()   Read the GS base register
   _writefsbase_u64()  Write the FS base register
   _writegsbase_u64()  Write the GS base register
   =================== ===========================