recipes: Drop remaining PR values from recipes

* as oe-core did in:
  https://git.openembedded.org/openembedded-core/commit/?id=d4c346e8ab

* when people are have to maintain own PRs for recipes in oe-core, they
  might add them for meta-oe recipes at the same time when upgrading
  to next LTS

Signed-off-by: Martin Jansa <martin.jansa@gmail.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-bsp/pointercal/pointercal_0.0.bb

@@ -1,6 +1,5 @@
 SUMMARY = "Touchscreen calibration data"
 SECTION = "base"
-PR = "r11"
 LICENSE = "MIT"
 LIC_FILES_CHKSUM = "file://COPYING;md5=4b5fcfc87fb615860d398b5e38685edf"