usb: renesas_usbhs: avoid uninitialized variable use

After the renesas_usbhs driver is enabled in ARM multi_v7_defconfig,
we now get a new warning:

renesas_usbhs/mod.c: In function 'usbhs_interrupt':
renesas_usbhs/mod.c:246:7: warning: 'intenb1' may be used uninitialized in this function [-Wmaybe-uninitialized]

gcc correctly points to a problem here, for the case that the
device is in host mode, we use the intenb1 variable without
having assigned it first. The state->intsts1 has a similar
problem, but gcc cannot know that.

This avoids the problem by initializing both sides of the
comparison to zero when we don't read them from the respective
registers.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 88a25e02 ("usb: renesas_usbhs: Add access control for INTSTS1 and INTENB1 register")
Acked-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>