graphics/nvidia-drm-kmod: Fix fetch

After e97a9e1fca31, graphics/nvidia-drm-515-kmod no longer fetches
because PORTREVISION was added to the Makefile. Since NVIDIA_GH_TAGNAME
was being derived from PKGNAME, adding PORTREVISION inadvertently
changed GH_TAGNAME for the port, therefore it did not match distinfo.

> amshafer-nvidia-driver-535.104.05-nvidia-drm-515-kmod-535.104.05_1_GH0.tar.gz is not in /usr/ports/graphics/nvidia-drm-515-kmod/distinfo.

> Either /usr/ports/graphics/nvidia-drm-515-kmod/distinfo is out of date, or

> amshafer-nvidia-driver-535.104.05-nvidia-drm-515-kmod-535.104.05_1_GH0.tar.gz is spelled incorrectly.

• Error code 1

Approved by: portmgr (blanket)
MFH: 2023Q4

(cherry picked from commit 0d5a698e4b4c31d7bdc94c11077109f74cdaceff)