Makefile: default toolchain path to stock GCC 4.7 toolchain

Change-Id: Ifebfff9cc05dc3987e5269147a7c2ed03fcf3a67
Signed-off-by: zwliew <zhaoweiliew@gmail.com>
arm: cache-l2x0: Fix variable undeclared build error

Undeclared 'cache_id' causes this build error:
error: 'cache_id' undeclared (first use in this function)

Change-Id: Ida91e7c0ab9434349fdfbab8c02d20dd9ddf6823
Signed-off-by: zwliew <zhaoweiliew@gmail.com>