spi: mtk_spim: Remove completion.h include

This created a conflict when linking.

Signed-off-by: John Watts <contact@jookia.org>
diff --git a/drivers/spi/mtk_spim.c b/drivers/spi/mtk_spim.c
index 90f4c3c..2979487 100644
--- a/drivers/spi/mtk_spim.c
+++ b/drivers/spi/mtk_spim.c
@@ -18,7 +18,6 @@
 #include <dm/devres.h>
 #include <dm/pinctrl.h>
 #include <linux/bitops.h>
-#include <linux/completion.h>
 #include <linux/dma-mapping.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>