sanitycheck: native: Removed --coverage from EXTRA_LDFLAGS
sanitycheck: native: Removed --coverage from EXTRA_LDFLAGS

Removed redundant linker flag --coverage from native posix
EXTRA_LDFLAGS.

The correct linker flags will be set by defining the Kconfig flag
CONFIG_COVERAGE, either by sanitcheck it self or via the test/sample
prj.conf.

Signed-off-by: Jan Van Winkel <d648848808a4d751aff880668aa63d2d9d94a5a4@dxplore.eu>

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