staging: easycap: fix sparse warnings 'Should it be static'

easycap_main.c:41:23: warning: symbol 'easycapdc60_dongle' was not declared. Should it be static?
easycap_main.c:49:22: warning: symbol 'easycap_usb_device_id_table' was not declared. Should it be static?
easycap_main.c:69:30: warning: symbol 'easycap_fops' was not declared. Should it be static?
easycap_main.c:82:29: warning: symbol 'easycap_vm_ops' was not declared. Should it be static?
easycap_main.c:87:25: warning: symbol 'easycap_class' was not declared. Should it be static?
easycap_main.c:95:35: warning: symbol 'v4l2_fops' was not declared. Should it be static?
easycap_main.c:5071:1: warning: symbol 'easycap_module_init' was not declared. Should it be static?
easycap_main.c:5101:1: warning: symbol 'easycap_module_exit' was not declared. Should it be static?
easycap_low.c:45:50: warning: symbol 'stk1160configPAL' was not declared. Should it be static?
easycap_low.c:87:28: warning: symbol 'stk1160configNTSC' was not declared. Should it be static?
easycap_low.c:129:50: warning: symbol 'saa7113configPAL' was not declared. Should it be static?
easycap_low.c:187:28: warning: symbol 'saa7113configNTSC' was not declared. Should it be static?
easycap_ioctl.c:915:5: warning: symbol 'adjust_mute' was not declared. Should it be static?
easycap_settings.c:42:31: warning: symbol 'easycap_standard' was not declared. Should it be static?
easycap_settings.c:312:23: warning: symbol 'easycap_format' was not declared. Should it be static?
easycap_settings.c:607:23: warning: symbol 'easycap_control' was not declared. Should it be static?

Cc: Mike Thomas <rmthomas@sciolus.org>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>