drivers: base: dma-mapping: Erase blank space after pointer

This patch fixes the following checkpatch.pl error:
ERROR: "foo * bar" should be "foo *bar"

Signed-off-by: Marius Cristian Eseanu <eseanu.cristian@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>