Add mmc and mmcsd, and correct a couple of comments. They are

commented out until I can re-test them on all our architectures.  I
had re@ approval to commit this a long time ago, but that's before we
were this close to the branch.

Approved by: re@

sys/conf/NOTES

@@ -1316,8 +1316,8 @@ options 	TTYHOG=8193
 # HARDWARE DEVICE CONFIGURATION
 
 # For ISA the required hints are listed.
-# EISA, MCA, PCI and pccard are self identifying buses, so no hints
-# are needed.
+# EISA, MCA, PCI, CardBus, SD/MMC and pccard are self identifying buses, so
+# no hints are needed.
 
 #
 # Mandatory devices:
@@ -2226,13 +2226,21 @@ device		bktr
 #
 # PC Card/PCMCIA and Cardbus
 #
-# pccbb: pci/cardbus bridge implementing YENTA interface
+# cbb: pci/cardbus bridge implementing YENTA interface
 # pccard: pccard slots
 # cardbus: cardbus slots
 device		cbb
 device		pccard
 device		cardbus
 
+#
+# MMC/SD
+#
+# mmc: mmc bus
+# mmcsd: mmc memory and sd cards.
+#device		mmc
+#device		mmcsd
+
 #
 # SMB bus
 #