linux-armv7: Specify system processor and fix library finding.
linux-armv7: Specify system processor and fix library finding.

This commit updates the toolchain to ensure libraries associated with arm
can be found. While a new root path needed to be set for armv6, the
most recent armv7 toolchain doesn't require to explicitly set a new
root.

dockcross/dockcross,dockcross/dockcross,thewtex/cross-compilers,dockcross/dockcross,thewtex/cross-compilers,dockcross/dockcross,thewtex/cross-compilers,thewtex/cross-compilers