bcma: remove bcma_pmu_{pll,swreg}_init()

These functions are doing nothing in the current code.

I do not think we will need these function in the future as the
corresponding functions in the Broadcom SDK are just doing something
useful on chips supported by ssb or fullmac chips.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>