arch/x86/car.ld: Rename suffix _start/_end

This is more in line with how linker symbol for regions are defined.

Change-Id: I0bd7ae59a27909ed0fd38e6f7193816cb57e76af
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36695
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/drivers/usb/ehci_debug.c

@@ -70,7 +70,7 @@ static inline struct ehci_debug_info *dbgp_ehci_info(void)
 			/* The message likely does not show if we hit this. */
 			if (sizeof(*info) > _car_ehci_dbg_info_size)
 				die("BUG: Increase ehci_dbg_info reserve in CAR");
-			info = (void *)_car_ehci_dbg_info_start;
+			info = (void *)_car_ehci_dbg_info;
 		} else {
 			info = &glob_dbg_info;
 		}