Staging: crystalhd: Fix sparse warnings regarding static functions

This fixes the following sparse warnings:
* drivers/staging/crystalhd/crystalhd_lnx.c:78:29: warning:
symbol 'chd_dec_alloc_iodata' was not declared. Should it be static?
* drivers/staging/crystalhd/crystalhd_lnx.c:99:6: warning:
symbol 'chd_dec_free_iodata' was not declared. Should it be static?
* drivers/staging/crystalhd/crystalhd_lnx.c:630:5: warning:
symbol 'chd_dec_pci_suspend' was not declared. Should it be static?
* drivers/staging/crystalhd/crystalhd_lnx.c:664:5: warning:
symbol 'chd_dec_pci_resume' was not declared. Should it be static?

Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>