dmaengine: stm32-mdma: remove MODULE_LICENSE in non-modules

Since commit 8b41fc4454e ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations
are used to identify modules. As a consequence, uses of the macro
in non-modules will cause modprobe to misidentify their containing
object file as a module when it is not (false positives), and modprobe
might succeed rather than failing with a suitable error message.

So remove it in the files in this commit, none of which can be built as
modules.

Signed-off-by: Nick Alcock <[e-mail]>
Suggested-by: Luis Chamberlain <[e-mail]>
Cc: Luis Chamberlain <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: Hitomi Hasegawa <[e-mail]>
Cc: Vinod Koul <[e-mail]>
Cc: Maxime Coquelin <[e-mail]>
Cc: Alexandre Torgue <[e-mail]>
Cc: Philipp Zabel <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Luis Chamberlain <[e-mail]>

drivers/dma/stm32-dmamux.c

···
 MODULE_DESCRIPTION("DMA Router driver for STM32 DMA MUX");
 MODULE_AUTHOR("M'boumba Cedric Madianga <[e-mail]>");
 MODULE_AUTHOR("Pierre-Yves Mordret <[e-mail]>");
-MODULE_LICENSE("GPL v2");

drivers/dma/stm32-mdma.c

···
 MODULE_DESCRIPTION("Driver for STM32 MDMA controller");
 MODULE_AUTHOR("M'boumba Cedric Madianga <[e-mail]>");
 MODULE_AUTHOR("Pierre-Yves Mordret <[e-mail]>");
-MODULE_LICENSE("GPL v2");