staging: gasket: fix multi line comments style

This patch fixes checkpatch.pl warnings:

WARNING: Block comments should align the * on each line
Signed-off-by: Felix Siegel <felix.siegel@posteo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/gasket/gasket_core.c

@@ -1507,7 +1507,7 @@ static enum do_map_region_status do_map_region(
  * Calculates the offset where the VMA range begins in its containing BAR.
  * The offset is written into bar_offset on success.
  * Returns zero on success, anything else on error.
-*/
+ */
 static int gasket_mm_vma_bar_offset(
 	const struct gasket_dev *gasket_dev, const struct vm_area_struct *vma,
 	ulong *bar_offset)