cross-canadian/libgcc: fix aarch64's multilib SDK

cross-canadian/libgcc: fix aarch64's multilib SDK

The arm toolchain has a "-gnueabi" suffix, but aarch64 doesn't,
this makes multilib sdk doesn't work, for example:

MACHINE = qemuarm64
require conf/multilib.conf
MULTILIBS = "multilib:lib32"
DEFAULTTUNE_virtclass-multilib-lib32 = "armv7at-neon"

$ bitbake core-image-minimal -cpopulate_sdk

Then extract SDK, the
environment-setup-armv7a-vfp-neon-pokymllib32-linux-gnueabi
doesn't work since:
* The CC is arm-pokymllib32-linux-gnueabi-gcc
  which doesn't exist, the patch for cross-canadian.bbclass
  fixes problem.
* Need aarch64-poky-linux/usr/lib/arm-poky-linux-linux-gnueabi
  which doesn't exist, the patch for libgcc-common.inc fixes the
  problem.

[YOCTO #8616]

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>