Kbuild: Pass absolute path to $(shell) commands

The PWD of the Kbuild script is the current source directory, whereas
the PWD of these $(shell) exectutables is the output directory, which is
usually different to keep the source directory clean.

Signed-off-by: Marijn Suijten <marijns95@gmail.com>
Change-Id: Icd8e445ecfd0dace36aca17e67782f01838d776f
diff --git a/Kbuild b/Kbuild
index 6d71214..5167ca1 100644
--- a/Kbuild
+++ b/Kbuild
@@ -3356,16 +3356,16 @@
 
 # inject some build related information
 ifeq ($(CONFIG_BUILD_TAG), y)
-CLD_CHECKOUT = $(shell cd "$(WLAN_ROOT)" && \
+CLD_CHECKOUT = $(shell cd "$(PWD)/$(WLAN_ROOT)" && \
 	git reflog | grep -vm1 "}: cherry-pick: " | grep -oE ^[0-f]+)
-CLD_IDS = $(shell cd "$(WLAN_ROOT)" && \
+CLD_IDS = $(shell cd "$(PWD)/$(WLAN_ROOT)" && \
 	git log -50 $(CLD_CHECKOUT)~..HEAD | \
 		sed -nE 's/^\s*Change-Id: (I[0-f]{10})[0-f]{30}\s*$$/\1/p' | \
 		paste -sd "," -)
 
-CMN_CHECKOUT = $(shell cd "$(WLAN_COMMON_INC)" && \
+CMN_CHECKOUT = $(shell cd "$(PWD)/$(WLAN_COMMON_INC)" && \
 	git reflog | grep -vm1 "}: cherry-pick: " | grep -oE ^[0-f]+)
-CMN_IDS = $(shell cd "$(WLAN_COMMON_INC)" && \
+CMN_IDS = $(shell cd "$(PWD)/$(WLAN_COMMON_INC)" && \
 	git log -50 $(CMN_CHECKOUT)~..HEAD | \
 		sed -nE 's/^\s*Change-Id: (I[0-f]{10})[0-f]{30}\s*$$/\1/p' | \
 		paste -sd "," -)