signlk.sh: do not check input file extension

Input file extension is meaningless.. the input file will very soon be openned
with ELFIO, and if it's not a valid ELF valid, the program will stop anyways, so
these checks are meaningless.

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>

signlk.sh

@@ -82,17 +82,6 @@ if [ "$INFILE" = "" ]; then
 fi
 
 INFILE_filename=$(echo $INFILE | rev | cut -f 2- -d '.' | rev)
-INFILE_extension=$(echo $INFILE | rev | cut -f 1 -d '.' | rev)
-
-if [ "$INFILE_extension" = "" ]; then
-   echo "input file must be an elf or mbn file"
-   exit 3      
-fi
-
-if [ "$INFILE_extension" != "elf" ] &&  [ "$INFILE_extension" != "mbn" ] && [ "$INFILE_extension" != "ELF" ] && [ "$INFILE_extension" != "MBN" ]; then
-   echo "input file must be an elf or mbn file"
-   exit 4
-fi
 
 if [ "$OUTFILE" = "" ]; then
         OUTFILE=$INFILE_filename"_signed.mbn"