Kernel/ACPI: Don't ask from TypedMapping to map 2 pages if unnecessary

Author: https://github.com/supercomputer7
Commit: 6282df3066
Pull-request: https://github.com/SerenityOS/serenity/pull/8241
Issue: https://github.com/SerenityOS/serenity/issues/6948
Issue: https://github.com/SerenityOS/serenity/issues/7445
Issue: https://github.com/SerenityOS/serenity/issues/8331
Reviewed-by: https://github.com/IdanHo
Reviewed-by: https://github.com/awesomekling

Kernel/ACPI/Parser.cpp

@@ -146,8 +146,7 @@ UNMAP_AFTER_INIT void Parser::init_fadt()
     m_fadt = find_table("FACP");
     VERIFY(!m_fadt.is_null());
 
-    // FIXME: We need at least two pages for mapping, since we can be on the "edge" of one page...
-    auto sdt = map_typed<const volatile Structures::FADT>(m_fadt, PAGE_SIZE * 2);
+    auto sdt = map_typed<const volatile Structures::FADT>(m_fadt);
 
     dbgln_if(ACPI_DEBUG, "ACPI: FADT @ V{}, {}", &sdt, m_fadt);