Move `PSR_Off` out of `Power_And_Clocks_Haswell`

Allowing other platforms to use the Haswell-specific power and clocks
package precludes with'ing other Haswell-specific units unless they are
placed under `haswell_shared` as well. This unnecessarily forces several
implementation-specific details to be public, breaking encapsulation.

The only benefit is that the `PSR_Off` procedure gets to be shared.
However, we can allow reusing said procedure without having to destroy
encapsulation, by moving it elsewhere. As the SRD/PSR registers are tied
to transcoders, place `PSR_Off` and the corresponding definitions to the
common `Transcoder` package. Also update the callers of this procedure
to refer to the `Transcoder` package, and then drop the visibility of
the power and clocks package for Haswell.

Change-Id: I7483409b8b7db58874cbba3c0a7edb1968bba456
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/libgfxinit/+/43563
Tested-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/common/hw-gfx-gma-transcoder.ads b/common/hw-gfx-gma-transcoder.ads
index b026933..4a24996 100644
--- a/common/hw-gfx-gma-transcoder.ads
+++ b/common/hw-gfx-gma-transcoder.ads
@@ -28,6 +28,8 @@
    procedure Off (Pipe : Pipe_Index);
    procedure Clk_Off (Pipe : Pipe_Index);
 
+   procedure PSR_Off;
+
    function BPC_Conf (BPC : BPC_Type; Dither : Boolean) return Word32;
 
 private