net: dsa: lan9303: lan9303_csr_reg_wait cleanups

Non-functional cleanups in lan9303_csr_reg_wait():
 - Change type of param 'mask' from int to u32.
 - Remove param 'value' (will probably never be used)
 - Reduced retries from 1000 to 25, consistent with lan9303_read_wait.
 - Removed comments

Signed-off-by: Egil Hjelmeland <privat@egil-hjelmeland.no>

Changes v1 -> v2:
 - Removed comments
Signed-off-by: David S. Miller <davem@davemloft.net>