spi: omap-100k: remove pointless _remove function

Commit [8074cf06: use devm_spi_register_master()] removed the last
bit of omap1_spi100k_remove function that had side effects.  After
call to spi_unregister_master was removed, the function consisted
of:

2. call to platform_get_drvdata whose return value was only used in:
2. call to spi_master_get_devdata whose return value was not used,
3. an if statement checking if zero was not zero, and
4. call to platform_get_resource whose return value was not used.

Ah, yes, and of course, final return 0. ;)

Since omap1_spi100k_remove no longer does anything, it can be
safely removed.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Mark Brown <broonie@linaro.org>