linux-user: Pass missing MAP_ANONYMOUS to target_mmap() call
A target_mmap() call in load_elf_binary() was missing the MAP_ANONYMOUS
flag. (Spotted by Coverity, because target_mmap() will try to use
-1 as the filedescriptor in this case.)
This has never been noticed because the code in question is for
handling ancient SVr4 iBCS2 binaries.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>