staging: dpaa2-switch: add a dpaa2_switch prefix to all functions in ethsw.c

Some static functions in the dpaa2-switch driver don't have a distinct
prefix and this is becoming an inconvenience when looking at, for
example, a perf top output and trying to determine easily which entries
are dpaa2 switch related. Ammend this by adding the prefix to all the
functions.
Signed-off-by: NIoana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/20201009153000.14550-3-ioana.ciornei@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>