webos-raspberrypi: Use WKS from upstream again

:Release Notes:
/boot minimal size was increased from 20MB to 100MB in:
agherzan/meta-raspberrypi#1290
agherzan/meta-raspberrypi@95a9103
so this (increase from minimal 20MB to fixed 80MB) is no longer needed.

:Detailed Notes:
Revert "meta-webos-raspberrypi: fix boot image partition size"
This reverts commit 2a33e0d337071288fdd6d14881335de5ee6e5429.

:Testing Performed:
build and runtime tested.
See the CCC ticket

:QA Notes:

:Issues Addressed:
[WRP-25796] CCC: meta-webos-raspberrypi: fix boot image partition size
[WRP-24777] [OSE-RPi4]:RPI-Device is not Rebooted , getting error as "Update fail".
[WRQ-504] Create GPVB with Yocto 5.0 Scarthgap

Change-Id: I2a8fb5646f4bc46e997be21ca866e74a36241dc2

meta-webos-raspberrypi/conf/machine/include/webos-rpi.inc

@@ -94,8 +94,5 @@ WEBOS_BLUETOOTH_ENABLED_SERVICE_CLASSES = "SPP GATT FTP OPP A2DP"
 SDIMG_ROOTFS_TYPE = "ext4"
 IMAGE_FSTYPES:remove = "ext3"
 
-# fixed size boot image
-WKS_FILE = "sdimage-raspberrypi-webos.wks"
-
 # Use Fake KMS until surface-manager is fixed to support Full KMS, see WRP-5
 VC4DTBO = "vc4-fkms-v3d"