fix(cmake): for embedded data length use .long attribute

For Linux builds if the embedded data length exceeded 16-bit value then
the build used to fail with following error:

build/x509_crt_bundle.S: Assembler messages:
build/x509_crt_bundle.S:4201: Warning: value 0x1056e truncated to 0x56e

GNU ASM for X86 systems treats .word attribute as of size 2 bytes, this commit
uses .long attribute to take the size to 4 bytes.

tools/cmake/scripts/data_file_embed_asm.cmake

@@ -83,4 +83,4 @@ if(FILE_TYPE STREQUAL "TEXT")
 else()
     make_and_append_identifier("${varname}_length")
 endif()
-append_line(".word ${data_len}")
+append_line(".long ${data_len}")