of: remove empty arch prom.h headers

Now that prom.h is optional, all the empty prom.h headers can be removed.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Grant Likely <grant.likely@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Git-commit: 5116b1defad7cec648384c2d1bc0b7460d305c93
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[imaund@codeaurora.org: resolve merge conflicts]
Signed-off-by: Ian Maund <imaund@codeaurora.org>