V4L/DVB (13626): gspca - many subdrivers: Fix some warnings.

V4L/DVB (13626): gspca - many subdrivers: Fix some warnings.

- gl860.c:332:15: warning: cast to restricted __le16
- gl860.c:333:15: warning: cast to restricted __le16
- gl860-mi1320.c:348:5: warning: symbol 'mi1320_camera_settings' was not declared. Should it be static?
- gl860-mi2020.c:772:5: warning: symbol 'mi2020_camera_settings' was not declared. Should it be static?
- m5602_ov9650.c:444:7: warning: symbol 'data' shadows an earlier one
- m5602_core.c:84:5: warning: symbol 'm5602_wait_for_i2c' was not declared. Should it be static?
- m5602_core.c:391:6: warning: symbol 'm5602_disconnect' was not declared. Should it be static?
- m5602_s5k4aa.c:530:23: warning: dubious: x | !y
- m5602_s5k4aa.c:575:23: warning: dubious: x | !y
- gspca.c:1196:13: warning: potentially expensive pointer subtraction
- mr97310a.c:70:5: warning: symbol 'force_sensor_type' was not declared. Should it be static?
- ov519.c:2025:4: warning: do-while statement is not a compound statement
- ov519.c:2063:4: warning: do-while statement is not a compound statement
- ov519.c:2089:4: warning: do-while statement is not a compound statement
- ov519.c:1985:34: warning: incorrect type in assignment (different base types)
- sn9c20x.c:1164:5: warning: symbol 'i2c_r1' was not declared. Should it be static?
- sn9c20x.c:1189:5: warning: symbol 'i2c_r2' was not declared. Should it be static?
- sn9c20x.c:2237:27: warning: right shift by bigger than source value
- sn9c20x.c:2237:27: warning: right shift by bigger than source value

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>