remove daisy and peach boards (todo: re-add)

bl1 bootloader blobs needed, and lbmk doesn't currently
auto-download these for insertion, so their presence in
the build system is problematic because people might build
these and think they work - they don't, due to the lack of
those bl1 blobs

notes about this are included in lbwww, on the compatibility
list. these can be re-added and tested later, when lbmk handles
those bl1 bootloader blobs

resources/u-boot/daisy_snow/board.cfg

@@ -1,2 +0,0 @@
-ubtree="default"
-arch="ARMv7"

resources/u-boot/daisy_spring/board.cfg

@@ -1,2 +0,0 @@
-ubtree="default"
-arch="ARMv7"

resources/u-boot/peach_pi/board.cfg

@@ -1,2 +0,0 @@
-ubtree="default"
-arch="ARMv7"

resources/u-boot/peach_pit/board.cfg

@@ -1,2 +0,0 @@
-ubtree="default"
-arch="ARMv7"