Add some new PE_IMAGE_DEBUG_TYPE values

IMAGE_DEBUG_TYPE_REPRO is defined in the latest version of the PE
specification [1]. The others are defined in Windows SDK headers and/or
reported by DUMPBIN.

[1] https://docs.microsoft.com/en-us/windows/win32/debug/pe-format

bfd/ChangeLog:

2020-01-16  Jon Turney  <jon.turney@dronecode.org.uk>

	* peXXigen.c (debug_type_names): Add names for new debug data type
	values.

include/ChangeLog:

2020-01-16  Jon Turney  <jon.turney@dronecode.org.uk>

	* coff/internal.h (PE_IMAGE_DEBUG_TYPE_VC_FEATURE)
	(PE_IMAGE_DEBUG_TYPE_POGO, PE_IMAGE_DEBUG_TYPE_ILTCG)
	(PE_IMAGE_DEBUG_TYPE_MPX, PE_IMAGE_DEBUG_TYPE_REPRO): Add.