package/gcc: remove arm soft patch

package/gcc: remove arm soft patch

The patch refers to [1] which says "Unfortuantely, arm-gcc defaults to
generating code for armv5t." Since we always explicitly pass the target
CPU for ARM, the default CPU shouldn't matter.

As suggested by Arnout [2], a test based on qemu_arm_versatile_defconfig
has been done without this patch and there is no regression.

[1] https://sourceware.org/ml/crossgcc/2008-05/msg00009.html
[2] http://lists.busybox.net/pipermail/buildroot/2018-May/222104.html

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>