soc/intel/alderlake: Remove TCSS DMA _DSM method

The kernel does not need TCSS DMA's _DSM method. This change simply
removes this method.

BUG=None
TEST=Built Alderlake image successfully.

Signed-off-by: John Zhao <john.zhao@intel.com>
Change-Id: I313f9c8913bb8cf54581c5460ac3fb1597291ad5
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51964
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/soc/intel/alderlake/acpi/tcss_dma.asl

@@ -82,8 +82,3 @@ Method (_PRW, 0)
 {
 	Return (Package() { 0x6D, 4 })
 }
-
-Method (_DSM, 4, Serialized)
-{
-	Return (Buffer() { 0 })
-}