phy: marvell: fix several minor bugs in comphy_probe

If fdtdec_get_int can't find speed, set COMPHY_SPEED_INVALID
If fdtdec_get_int can't find type, set COMPHY_TYPE_INVALID
Move the error print if phy-type is invalid
Add continue to the probe loop (in a case of invalid phy)
Cosmetic changes

Change-Id: I0c61b40bfe685437426fe907942ed338b7845378
Signed-off-by: Igal Liberman <igall@marvell.com>