MAINTAINERS: Remove Andrew F. Davis

Andrews TI email is no longer valid and he indicated that it is
OK to remove him from the MAINTAINERS file for the DMA HEAPS FRAMEWORK.

For the BQ27xxx list I replaced Andrews email with mine.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>