target/m68k: fix physical address translation in m68k_cpu_get_phys_page_debug()

target/m68k: fix physical address translation in m68k_cpu_get_phys_page_debug()

The result of the get_physical_address() function should be combined with the
offset of the original page access before being returned. Otherwise the
m68k_cpu_get_phys_page_debug() function can round to the wrong page causing
incorrect lookups in gdbstub and various "Disassembler disagrees with
translator over instruction decoding" warnings to appear at translation time.

Fixes: 88b2fef6c3 ("target/m68k: add MC68040 MMU")
Signed-off-by: Mark Cave-Ayland <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Reviewed-by: Laurent Vivier <[email protected]>
Message-Id: <20200701201531[email protected]>
Signed-off-by: Laurent Vivier <[email protected]>