Revert "arm: dma-mapping: WARN_ON if iova is not 128M aligned"

This reverts commit 919aec60 ("arm: dma-mapping: WARN_ON if iova
is not 128M aligned")
This warning is unnecessary and is forcing the clients to use the 128M
aligned virtual address. This warning is introduced thinking that the
clients may unnecessarily lose the unaligned part in the VA higher
end.But that's okay as this is just a VA and at the maximum user can
lost the 128M - 1 bytes of VA. And the minimum VA is represented as
always 128M. All these calculations are around the 4K page size.

Change-Id: Id17c9a1894a6703eab0d4df370a064584ebe9c07
Signed-off-by: Prakash Gupta <guptap@codeaurora.org>