USB: EHCI: ehci-mv: fix less than zero comparison of an unsigned int

USB: EHCI: ehci-mv: fix less than zero comparison of an unsigned int

The comparison of hcd->irq to less than zero for an error check will
never be true because hcd->irq is an unsigned int.  Fix this by
assigning the int retval to the return of platform_get_irq and checking
this for the -ve error condition and assigning hcd->irq to retval.

Addresses-Coverity: ("Unsigned compared against 0")
Fixes: c856b4b0fdb5 ("USB: EHCI: ehci-mv: fix error handling in mv_ehci_probe()")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20200515165453.104028-1-colin.king@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>