accel/amdxdna: Create common SMU interfaces for AIE2 and AIE4

accel/amdxdna: Create common SMU interfaces for AIE2 and AIE4

AIE2 and AIE4 use similar interfaces to the SMU (System Management
Unit). Move the SMU implementation into aie_smu.c and provide common
interfaces for both platforms.

This allows AIE2 and AIE4 to share the same implementation and reduces
code duplication.

Co-developed-by: Hayden Laccabue <Hayden.Laccabue@amd.com>
Signed-off-by: Hayden Laccabue <Hayden.Laccabue@amd.com>
Signed-off-by: David Zhang <yidong.zhang@amd.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Link: https://patch.msgid.link/20260330163705.3153647-6-lizhi.hou@amd.com