Update floating-point dot product bounds

- Apply element-wise `max(abs(x), normal_min)` to handle subnormal
values and ensure numerical stability in bounds mode.

- Updated ops: CONV2D, CONV3D, DEPTHWISE_CONV2D, MATMUL,
TRANSPOSE_CONV2D, FFT2D, RFFT2D, AVG_POOL2D

Co-authored-by: Ian Tayler Lessa <ian.taylerlessa@arm.com>
Signed-off-by: Peng Sun <peng.sun@arm.com>
Change-Id: I5a2c3a44be647c5acb08d67e045af8250f9380bc