net: stmmac: reorganise stmmac_hwif_init()

net: stmmac: reorganise stmmac_hwif_init()

Reorganise stmmac_hwif_init() to handle the error case of
stmmac_hwif_find() in the indented block, which follows normal
programming pattern.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Tested-by: Mohd Ayaan Anwar <mohd.anwar@oss.qualcomm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vDtfG-0000000CCCX-2YwQ@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>