linux-yocto-tiny: fix KBRANCH

linux-yocto-tiny: fix KBRANCH

Fixed:
WARNING: linux-yocto-tiny-4.4.3+gitAUTOINC+770996a263_73481a3abd-r0 do_patch: After meta data application, the kernel tree branch is standard/tiny/common-pc. The
WARNING: linux-yocto-tiny-4.4.3+gitAUTOINC+770996a263_73481a3abd-r0 do_patch: SRC_URI specified branch standard/tiny/base. The branch will be forced to standard/tiny/base,
WARNING: linux-yocto-tiny-4.4.3+gitAUTOINC+770996a263_73481a3abd-r0 do_patch: but this means the board meta data (.scc files) do not match the SRC_URI specification.
WARNING: linux-yocto-tiny-4.4.3+gitAUTOINC+770996a263_73481a3abd-r0 do_patch: The meta data and branch standard/tiny/base should be inspected to ensure the proper
WARNING: linux-yocto-tiny-4.4.3+gitAUTOINC+770996a263_73481a3abd-r0 do_patch: kernel is being built.

Use standard/tiny/common-pc which is pointed by the .scc to fix problem.
Btw, standard/tiny/base and standard/tiny/common-pc points to the same
commit id.

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