Fix clean target; add objdump gen on build.

Noticed the clean target for ARM didn't actually clean the directory.
Found a fix at
http://stackoverflow.com/questions/3048684/makefile-and-rm-f-file-ext1-ext2-ext3-issue

Added generation of objdump file to the build process.
Revert "Fix clean target; add objdump gen on build."

This reverts commit 81ac106b3349f359cd18dd13c7b5ae75f350250e.

Will make the two changes to two commits.
Fix clean target

clean target for ARM was not deleting files in the ./boot directory.
http://stackoverflow.com/questions/1338728/how-can-i-delete-a-git-commit
suggests that make uses /bin/sh by default, which does not expand
the extension pattern-matching syntax that the makefile uses.
Specified that the makefile should use bash.
Add kernel map

Added generation of a kernel map to ARM build sequence.