ANDROID: 16K: Fix show maps CFI failure

If the kernel is built CONFIG_CFI_CLANG=y, reading smaps
may cause a panic. This is due to a failed CFI check; which
is triggered becuase the signature of the function pointer for
printing smaps padding VMAs does not match exactly with that
for show_smap().

Fix this by casting the function pointer to the expected type
based on whether printing maps or smaps padding.

Bug: 330117029
Bug: 327600007
Bug: 330767927
Bug: 328266487
Bug: 329803029
Change-Id: I65564a547dacbc4131f8557344c8c96e51f90cd5
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>