sconfig: Add a new mmio resource type

Add support for a mmio resource in the devicetree to allow
memory-mapped IO addresses to be assigned to given values.

AMD platforms perform a significant amount of configuration through
these MMIO addresses, including I2C bus configuration.

BUG=b:72121803

Change-Id: I5608721c22c1b229f527815b5f17fff3a080c3c8
Signed-off-by: Justin TerAvest <teravest@chromium.org>
Reviewed-on: https://review.coreboot.org/23319
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

util/sconfig/sconfig.tab.h_shipped

@@ -30,8 +30,8 @@
    This special exception was added by the Free Software Foundation in
    version 2.2 of Bison.  */
 
-#ifndef YY_YY_SCONFIG_TAB_H_SHIPPED_INCLUDED
-# define YY_YY_SCONFIG_TAB_H_SHIPPED_INCLUDED
+#ifndef YY_YY_UTIL_SCONFIG_SCONFIG_TAB_H_SHIPPED_INCLUDED
+# define YY_YY_UTIL_SCONFIG_SCONFIG_TAB_H_SHIPPED_INCLUDED
 /* Debug traces.  */
 #ifndef YYDEBUG
 # define YYDEBUG 0
@@ -72,7 +72,8 @@ extern int yydebug;
     IOAPIC = 282,
     PCIINT = 283,
     GENERIC = 284,
-    SPI = 285
+    SPI = 285,
+    MMIO = 286
   };
 #endif
 
@@ -100,4 +101,4 @@ extern YYSTYPE yylval;
 
 int yyparse (void);
 
-#endif /* !YY_YY_SCONFIG_TAB_H_SHIPPED_INCLUDED  */
+#endif /* !YY_YY_UTIL_SCONFIG_SCONFIG_TAB_H_SHIPPED_INCLUDED  */