fix(qemu-sbsa): fix compilation error when accessing DT functions

When building SBSA, using DT functions from fdt_wrappers.c produces a
linker error.  Adding:

BL2_SOURCES += ${FDT_WRAPPERS_SOURCES}

fixes the problem.  Since the same inclusion would be present in both
qemu/platform.mk and qemu_sbsa/platform.mk, do the changes in
qemu/common/common.mk.

Change-Id: I775b06c1741f6618813c5e1d2c64cdc1888d8519
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
3 files changed