mmc: sd: return error information of sd_init_card incase of failure

During _mmc_sd_resume, if sd card initialization fails, the error
information is getting overwritten by mmc_resume_clk_scaling and the
error is not passed to caller function.

Change-Id: Id173e2db65024f12a714ec623668e47c540a56c3
Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>