[EMULATORS] Apropriate locking in emulation layer functions.

Locking was completely missing in the previous version.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
[EMULATORS] Rename pci_emu_xxx_config_space

Renamed pci_emu_read_config_space & pci_emu_write_config_space
to pci_emu_config_space_read & pci_emu_config_space_write.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>