mmc: sdricoh_cs: remove unused sdricoh_readw function

clang with W=1 reports
drivers/mmc/host/sdricoh_cs.c:104:28: error: unused function
  'sdricoh_readw' [-Werror,-Wunused-function]
static inline unsigned int sdricoh_readw(struct sdricoh_host *host,
                           ^
This function is not used, so remove it.

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20230319164744.1707169-1-trix@redhat.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>