ANDROID: GKI: remove info print for header generation

Script doesn't honor the Kernel's quiet command
mechanism with KBuild; so need to remove info
only echo. Added set -x in case make V=1 for keeping
debugging handy for script in the future.

Bug: 234116152
Test: TH
Signed-off-by: Ramji Jiyani <ramjiyani@google.com>
Change-Id: Iea881816b9bc8c47157a33da67d6cf5f8357a7be
(cherry picked from commit 08a1879c)