Fix arm-linux default toolchain file

The toolchain file was incorrectly setting the xx_INIT variables and
thus losing value set in initial cache file.
This patch switches to string(APPEND ...) to avoid overwriting data.

Change-Id: Ie8a0b2d624fdcc859861a62199f6ccb8df51e087
Signed-off-by: Gyorgy Szing <Gyorgy.Szing@arm.com>
1 file changed