Revert "Reenable support for non-PIE executables"

For testing

This reverts commit 2a80dc3bf133efc94e36c0c96ecde0e67361aca7.
linker: don't fail if executable is not position independent

Warn but don't fail if the executable that we are dealing with is
not position independant. A lot of device prebuilt blobs would
fail if PIE checks are strictly enforced. (rild, gpsd, etc.)

Change-Id: I2e52af04bd5d34d142d03631d3bfd7d58ebe0ca6