Remove const warning (#158)

Remove const warning (#158)

* Remove spurious trailing spaces

* Add missing const on the pointed data

This removes compilation warning:
Building C object _deps/ocl-icd-build/CMakeFiles/OpenCL.dir/loader/linux/icd_linux.c.o
In file included from _deps/ocl-icd-src/loader/icd.h:22,
                 from _deps/ocl-icd-src/loader/linux/icd_linux.c:19:
_deps/ocl-icd-src/loader/linux/icd_linux.c: In function ‘khrIcdOsVendorsEnumerate’:
_deps/ocl-icd-src/loader/icd_platform.h:29:25: warning: initialization discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
   29 | #define ICD_VENDOR_PATH "/etc/OpenCL/vendors";
      |                         ^~~~~~~~~~~~~~~~~~~~~
_deps/ocl-icd-src/loader/linux/icd_linux.c:43:24: note: in expansion of macro ‘ICD_VENDOR_PATH’
   43 |     char* vendorPath = ICD_VENDOR_PATH;
      |                        ^~~~~~~~~~~~~~~