Mailbox_to_SDM Address Map

Door Bell registers to allow RW by both SDM and external masters

Module Instance	Base Address	End Address
`i_mailbox_tosdm`	`0xFFA30400`	`0xFFA3040B`

Register	Offset	Width	Access	Reset Value	Description
`em2sdm`	`0x0`	`32`	`RW`	`0x00000000`	reg