cmake: removed stray space in readelf in-/outfile flag
cmake: removed stray space in readelf in-/outfile flag

Removed stray whitespace in readelf infile and outfile flag.

Some bintools use `--arg=<val>`, others `--arg <val>` therefore the call
at this location should not force a space, as that will fail on tools
using `=`, as this becomes: `--arg= <val>`

Signed-off-by: Torsten Rasmussen <a7c5b1d5a1f41fce6edfa3f7c2392ae0c59deafe@nordicsemi.no>

zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr