mmc: arm_pl180_mmci: Don't bind to all arm, primecell devices

The arm,primecell compatible is used for lots of different types
of devices, e.g. I2C, SPI, coresight, ... We really should not bind
the MMC driver to all of them.

Looking through the device trees in U-Boot there seems to be always
a second compatible string for the pl180 device, either arm,pl180
(already listed) or arm,pl18x. Add the "arm,pl18x" compatible to the
list but remove the generic "arm,primecell".

Note that on Linux these compatibles cannot be found in drivers
because AMBA/primecell devices are matched based on their peripheral ID
instead of the compatible.

This fixes the following error messages when booting the ST-Ericsson
U8500 "stemmy" board with the arm_pl180_mmci driver enabled:

  MMC:   ptm@801ae000 - probe failed: -38
  ptm@801af000 - probe failed: -38
  funnel@801a6000 - probe failed: -38
  tpiu@80190000 - probe failed: -38
  etb@801a4000 - probe failed: -38

Cc: Patrice Chotard <patrice.chotard@st.com>
Fixes: 6f41d1a1 ("mmc: arm_pl180_mmci: Sync compatible with kernel")
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Tested-by: Patrice Chotard <patrice.chotard@foss.st.com> on stm32f769-disco
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>