[uaccess] Remove redundant memcpy_user() and related string functions

The memcpy_user(), memmove_user(), memcmp_user(), memset_user(), and
strlen_user() functions are now just straightforward wrappers around
the corresponding standard library functions.

Remove these redundant wrappers.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/interface/smbios/smbios.c

@@ -277,7 +277,7 @@ int read_smbios_string ( struct smbios_structure *structure,
 		 * smbios_strings struct is constructed so as to
 		 * always end on a string boundary.
 		 */
-		string_len = strlen_user ( smbios.address, offset );
+		string_len = strlen ( smbios.address + offset );
 		if ( --index == 0 ) {
 			/* Copy string, truncating as necessary. */
 			if ( len > string_len )