OvmfPkg/ResetVector: Depend on PCD values of the page tables.

OvmfPkg/ResetVector: Depend on PCD values of the page tables.

Currently, the value of the page tables' address is hard-coded in the
ResetVector. This patch replaces these values with a PCD dependency.

A check for the size has been added to alert the developer to rewrite
the ASM according to the new size, if it has been changed.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Marvin Haeuser <Marvin.Haeuser@outlook.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>