Fix a race condition if the clock provider comes up after mmc is probed,
this causes mmc to fail without retrying.
When given the DEFER error from the clk source, pass it on up the chain.

Fixes: f90a0612 ("mmc: dw_mmc: lookup for optional biu and ciu clocks")
Signed-off-by: Ben Whitten <ben.whitten@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240811212212.123255-1-ben.whitten@gmail.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>