dmaengine: tegra: Fix burst size calculation

In the Linux kernel, the following vulnerability has been resolved: dmaengine: tegra: Fix burst size calculation Currently, the Tegra GPC DMA hardware requires the transfer length to be a multiple of the max burst size configured for the channel. When a client requests a transfer where the length is not evenly divisible by the configured max burst size, the DMA hangs with partial burst at the end. Fix this by reducing the burst size to the largest power-of-2 value that evenly divides the transfer length. For example, a 40-byte transfer with a 16-byte max burst will now use an 8-byte burst (40 / 8 = 5 complete bursts) instead of causing a hang. This issue was observed with the PL011 UART driver where TX DMA transfers of arbitrary lengths were stuck.