net: stmmac: clear reset value of snps, wr_osr_lmt/snps, rd_osr_lmt before writing
WR_OSR_LMT and RD_OSR_LMT have a reset value of 1.
Since the reset value wasn't cleared before writing, the value in the
register would be incorrect if specifying an uneven value for
snps,wr_osr_lmt/snps,rd_osr_lmt.
Zero is a valid value for the properties, since the databook specifies:
maximum outstanding requests = WR_OSR_LMT + 1.
We do not want to change the behavior for existing users when the
property is missing. Therefore, default to 1 if the property is missing,
since that is the same as the reset value.
Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>