usb: renesas_usbhs: simplify usbhs_status_get_device_state()

Similar to usbhs_status_get_ctrl_stage(), *_get_device_state() is not
supposed to return any error code since its return value is the DVSQ
bitfield of the INTSTS0 register. According to SoC HW manual rev1.00,
every single value of DVSQ[2:0] is valid and none is an error:

----8<----
Device State
000: Powered state
001: Default state
010: Address state
011: Configuration state
1xx: Suspended state
----8<----

Hence, simplify the function body. The motivation behind dropping the
switch/case construct is being able to implement reading the suspended
state. The latter (based on the above DVSQ[2:0] description) doesn't
have a unique value, but is rather a list of states (which makes
switch/case less suitable for reading/validating it):

100: (Suspended) Powered state
101: (Suspended) Default state
110: (Suspended) Address state
111: (Suspended) Configuration state
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Veeraiyan Chidambaram <veeraiyan.chidambaram@in.bosch.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/1568207756-22325-1-git-send-email-external.veeraiyan.c@de.adit-jv.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/renesas_usbhs/mod.c

@@ -169,17 +169,7 @@ void usbhs_mod_remove(struct usbhs_priv *priv)
  */
 int usbhs_status_get_device_state(struct usbhs_irq_state *irq_state)
 {
-	int state = irq_state->intsts0 & DVSQ_MASK;
-
-	switch (state) {
-	case POWER_STATE:
-	case DEFAULT_STATE:
-	case ADDRESS_STATE:
-	case CONFIGURATION_STATE:
-		return state;
-	}
-
-	return -EIO;
+	return (int)irq_state->intsts0 & DVSQ_MASK;
 }
 
 int usbhs_status_get_ctrl_stage(struct usbhs_irq_state *irq_state)