[SYCL][DOC] DeviceLib doc update to add new supported items (#3623)

* update devicelib doc

Signed-off-by: gejin <ge.jin@intel.com>

sycl/doc/extensions/C-CXX-StandardLibrary/C-CXX-StandardLibrary.rst

@@ -53,6 +53,9 @@ List of supported functions from C standard library:
   - acoshf, acosh         (from <math.h> or <cmath>)
   - asinhf, asinh         (from <math.h> or <cmath>)
   - atanhf, atanh         (from <math.h> or <cmath>)
+  - scalbnf, scalbn       (from <math.h> or <cmath>)
+  - abs, labs, llabs      (from <stdlib.h> or <cstdlib>)
+  - div, ldiv, lldiv      (from <stdlib.h> or <cstdlib>)
   - cimagf, cimag         (from <complex.h>)
   - crealf, creal         (from <complex.h>)
   - cargf, carg           (from <complex.h>)
@@ -84,19 +87,6 @@ a baseline.
 NOTE: Only the GNU glibc, Microsoft C libraries are currently
 supported. Not all functions from <math.h> are supported right now,
 following math functions are not supported now:
- - abs
- - ceilf, ceil
- - copysignf, copysign
- - fabsf, fabs
- - floorf, floor
- - fmaxf, fmax
- - fminf, fmin
- - nextafterf, nextafter
- - rintf, rint
- - roundf, round
- - truncf, trunc
- - scalbnf, scalbn
- - nearbyintf, nearbyint
  - lrintf, lrint
  - nexttowardf, nexttoward
  - nanf, nan

sycl/doc/extensions/C-CXX-StandardLibrary/DeviceLibExtensions.rst

@@ -37,6 +37,13 @@ cl_intel_devicelib_math
 ==========================
 
 .. code:
+   int    __devicelib_abs(int x);
+   int    __devicelib_labs(long int x);
+   int    __devicelib_llabs(long long int x);
+   int    __devicelib_div(int x, int y);
+   int    __devicelib_ldiv(long int x, long int y);
+   int    __devicelib_lldiv(long long int x, long long int y);
+   float  __devicelib_scalbnf(float x, int n);
    float  __devicelib_logf(float x);
    float  __devicelib_sinf(float x);
    float  __devicelib_cosf(float x);
@@ -90,6 +97,7 @@ cl_intel_devicelib_math_fp64
 ==========================
 
 .. code:
+   double __devicelib_scalbn(double x, int exp);
    double __devicelib_log(double x);
    double __devicelib_sin(double x);
    double __devicelib_cos(double x);