Revert "soc: intel_adsp/ace30: do not map 0x0"

This reverts commit 3d3ffa2c.

The original commit aimed to prevent NULL pointer accesses by moving the
MMU mapping starting point one page later. However, this change has
caused a regression on PTL. Our DSP has registers with addresses lower
than 0x1000, and the firmware uses addresses starting from 0xC40. For
instance, the HDAMLDMICL register is located at 0xCC0, which is now
inaccessible due to the change.

Reverting this commit restores access to these critical registers and
resolves the regression issue.

Signed-off-by: Tomasz Leman <tomasz.m.leman@intel.com>