subprojects: Fix libpeci provide variable name

Since its introduction in libpeci with df5c868a14eb ("Declare meson
dependency") the variable has been named `libpeci_dep`. It also appears
that since its inception in 77141acb7f09 ("IntelCPUSensor: Use libpeci
when communicating via peci-legacy") the variable name has been wrong in
the dbus-sensors wrap.

Fix the debus-sensors wrap so we can build with libpeci as a meson
subproject.

Tested:

Before:

```
$ meson subprojects purge --confirm && rm -rf build
...
$ meson setup build
...
Executing subproject libpeci

libpeci| Project name: libpeci
libpeci| Project version: 1.0
libpeci| C compiler for the host machine: ccache cc (gcc 12.2.0 "cc (Debian 12.2.0-14) 12.2.0")
libpeci| C linker for the host machine: cc ld.mold 1.10.1
libpeci| C++ compiler for the host machine: ccache c++ (gcc 12.2.0 "c++ (Debian 12.2.0-14) 12.2.0")
libpeci| C++ linker for the host machine: c++ ld.mold 1.10.1
libpeci| Dependency sdbusplus found: YES 1.0.0 (cached)
libpeci| Dependency systemd found: YES 252 (cached)
libpeci| Dependency boost found: YES 1.81.0 (cached)
libpeci| Build targets in project: 664
libpeci| Subproject libpeci finished.

WARNING: Variable 'peci_dep' in the subproject 'subprojects/libpeci' is not found
Dependency libpeci from subproject subprojects/libpeci found: NO

src/meson.build:64:15: ERROR: Dependency 'libpeci' is required but not found.
```

After:

```
$ meson setup build
...
Executing subproject libpeci

libpeci| Project name: libpeci
libpeci| Project version: 1.0
libpeci| C compiler for the host machine: ccache cc (gcc 12.2.0 "cc (Debian 12.2.0-14) 12.2.0")
libpeci| C linker for the host machine: cc ld.mold 1.10.1
libpeci| C++ compiler for the host machine: ccache c++ (gcc 12.2.0 "c++ (Debian 12.2.0-14) 12.2.0")
libpeci| C++ linker for the host machine: c++ ld.mold 1.10.1
libpeci| Dependency sdbusplus found: YES 1.0.0 (cached)
libpeci| Dependency systemd found: YES 252 (cached)
libpeci| Dependency boost found: YES 1.81.0 (cached)
libpeci| Build targets in project: 664
libpeci| Subproject libpeci finished.

Dependency libpeci from subproject subprojects/libpeci found: YES 1.0
...
```

Change-Id: I18f9e89a25c184d7fdc38aea01ff5dbee118a974
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
diff --git a/subprojects/libpeci.wrap b/subprojects/libpeci.wrap
index 59fc2b9..521591b 100644
--- a/subprojects/libpeci.wrap
+++ b/subprojects/libpeci.wrap
@@ -3,4 +3,4 @@
 revision = HEAD
 
 [provide]
-libpeci = peci_dep
\ No newline at end of file
+libpeci = libpeci_dep